All questions of Elementary Statistics for Electrical Engineering (EE) Exam

Class mark of a particular class is 9.5 and the class size is 6, then the class interval is
  • a)
    15.5-27.5
  • b)
    12.5-18.5
  • c)
    3.5-15.5
  • d)
    6.5-12.5
Correct answer is option 'D'. Can you explain this answer?

Anita Menon answered
Class mark = 9.5

=> Upper limit + Lower limit / 2 = 9.5

=> u + l = 19 -------(1)

Class mark = 6

=> u - l = 6 --------(2)

On adding equation 1 and 2, we get

2u = 25

=> u = 12.5

l = 6.5

Class interval is ( 6.5 - 12.5)

Primary data is gathered through
  • a)
    original source of information.
  • b)
    information on website.
  • c)
    second hand information.
  • d)
    annual company reports.
Correct answer is option 'A'. Can you explain this answer?

A primary data source is an original data source, that is, one in which the data are collected firsthand by the researcher for a specific research purpose or project. Primary data collection is quite expensive and time consuming compared to secondary 

Value that divides the series into hundred equal parts is called
  • a)
    percentile.
  • b)
    quartiles.
  • c)
    deciles.
  • d)
    octiles.
Correct answer is option 'A'. Can you explain this answer?

Kiran Mehta answered
Values that divide the series into hundred equal parts are called percentiles. In percentile, we get 99 dividing positions denoted by P1, P2,……..,P99.

Orderly arrangement of data according to magnitude is called
  • a)
    raw series.
  • b)
    individual series.
  • c)
    original series.
  • d)
    listed series.
Correct answer is option 'B'. Can you explain this answer?

When the raw data is presented individually in the form of a series, it is called an individual series.
In simple words, individual series is the arrangement of raw data individually. It gives numeric values for a specific situation.
In an individual series items are shown separately. So organisation on the basis of magnitude is individual series.

After collection of data, the next step is
  • a)
    presentation of data.
  • b)
    classification of data.
  • c)
    selection of data.
  • d)
    categorising of data.
Correct answer is option 'B'. Can you explain this answer?

Naina Sharma answered
Classification is the process of arranging data into different groups or classes.
► Classification of data is done after collection of data.

Data collected from the original source of information is called
  • a)
    primary data.
  • b)
    secondary data.
  • c)
    published data.
  • d)
    used data.
Correct answer is option 'A'. Can you explain this answer?

Arun Yadav answered
These are collected from the very source of information. They are collected for the first time from the original source of information.

Which of the following is not a measure of central tendency?
  • a)
    Mean
  • b)
    Median
  • c)
    Standard deviation
  • d)
    Mode
Correct answer is option 'C'. Can you explain this answer?

Om Desai answered
► Standard deviation is the measure of how spread out the numbers of a data are.
► Mean is the average.
► Median is the middle number, when data is arranged in numerical order.
► Mode is the data item the appears most frequently.
Mean, median and mode are all measures of central tendencies.

In an examination, ten students scored the following marks: 60, 58, 90, 51, 47, 81, 70, 95, 87, 99. The range of this data is
  • a)
    60
  • b)
    51
  • c)
    61
  • d)
    52
Correct answer is option 'D'. Can you explain this answer?

Given data: 60, 58, 90, 51, 47, 81, 70, 95, 87, 99
Range = difference between the highest and the lowest value in the data
To find the range, we need to first arrange the data in ascending or descending order.

Arranging the data in ascending order:
47, 51, 58, 60, 70, 81, 87, 90, 95, 99

Range = highest value - lowest value
Range = 99 - 47
Range = 52

Therefore, the correct answer is option 'D' (52).

The mean of five observations is 15. If the mean of first three observations is 14 and that of last three is 17, then the third observation is
  • a)
    29
  • b)
    31
  • c)
    32
  • d)
    18
Correct answer is option 'D'. Can you explain this answer?

Naina Sharma answered
⇒  It is given that Mean of 5 observations is 15.
∴  The sum of observations =15×5=75.
∴  It is given that mean of the first 3 observations is 14.
∴  The sum of first three observations =14×3=42.
⇒  Given that mean of the last 3 observations is 17.
∴  The sum of the last three observations =17×3=51
∴  The third observation =(42+51)−75
 =93−75
=18

Class mark of a particular class is 9.5 and the class size is 6, then the class interval is
  • a)
    3.5-15.5
  • b)
    12.5-18.5
  • c)
    15.5-27.5
  • d)
    6.5-12.5
Correct answer is option 'D'. Can you explain this answer?

To determine the class interval, we need to know the range of the data and the number of class intervals.

In this case, the class mark is given as 9.5 and the class size is 6. The class mark represents the midpoint of the class interval, which means that the lower limit of the class interval is 9.5 - 0.5 = 9 and the upper limit is 9.5 + 0.5 = 10.

Let's calculate the range of the data:
Range = Upper Limit - Lower Limit
Range = 10 - 9
Range = 1

Since the range is 1 and there are 6 class intervals, we can divide the range by the number of class intervals to determine the class interval size:
Class Interval Size = Range / Number of Class Intervals
Class Interval Size = 1 / 6
Class Interval Size = 0.1667

Now, we can determine the class intervals:
First Class Interval: 9 - 9.1667
Second Class Interval: 9.1667 - 9.3333
Third Class Interval: 9.3333 - 9.5
Fourth Class Interval: 9.5 - 9.6667
Fifth Class Interval: 9.6667 - 9.8333
Sixth Class Interval: 9.8333 - 10

As we can see, the class interval that includes the class mark of 9.5 is 9.5 - 9.6667. Therefore, the correct answer is option D) 6.5-12.5.

It is important to note that the other options given are incorrect because they do not include the class mark of 9.5 within the range of the class intervals.

The width of each of five continuous classes in a frequency distribution is 5 and the lower class limit of the lowest class is 10. The upper class limit of the highest class is
  • a)
    15
  • b)
    40
  • c)
    25
  • d)
    35
Correct answer is option 'D'. Can you explain this answer?

Vikas Kapoor answered
Let x and y be the upper and lower class limit of frequency distribution.
Given, width of the class = 5
⇒ x-y= 5 …(i)
Also, given lower class (y) = 10 On putting y = 10 in Eq. (i), we get
x – 10= 5 ⇒  x = 15 So, the upper class limit of the lowest class is 15.
Hence, the upper class limit of the highest class
=(Number of continuous classes x Class width + Lower class limit of the lowest class)
= 5 x 5+10 = 25+10=35
Hence,’the upper class limit of the highest class is 35.
Alternate Method
After finding the upper class limit of the lowest class, the five continuous classes in a frequency distribution with width 5 are 10-15,15-20, 20-25, 25-30 and 30-35.
Thus, the highest class is 30-35,
Hence, the upper limit of this class is 35.

On the basis of presence and absence of an attribute, data are classified into
  • a)
    one fold classification.
  • b)
    two fold classification.
  • c)
    three fold classification.
  • d)
    four fold classification.
Correct answer is option 'B'. Can you explain this answer?

Sunil Chahar answered
When on the basis  presence and absence of an attribute, the data are classified into two classes, one possessing that attribute and the other not possessing that attribute, it is called two-fold classification.

More than one attribute are present simultaneously in case of
  • a)
    qualitative classification.
  • b)
    quantitative classification.
  • c)
    manifold classification.
  • d)
    chronological classification.
Correct answer is option 'C'. Can you explain this answer?

Vikas Kapoor answered
In manifold classification, two or more attributes are considered simultaneously. When more attributes are involved, the data would be classified into several classes and subclasses depending on the number of attributes.
For example, the population in a country can be classified in terms of gender as male and female.
The correct option is Option C

Classification of data is the grouping of raw data under different
  • a)
    headings
  • b)
    rows
  • c)
    columns
  • d)
    tables
Correct answer is option 'A'. Can you explain this answer?

Vikas Kapoor answered
Classification is concerned with the division of the data into various groups and sub groups.
► Data is classified into groups of different headings.

A student collects information about the number of school going children in a locality consisting of a hundred households. The data collected by him is
  • a)
    Arrayed data
  • b)
    Grouped data
  • c)
    Primary data
  • d)
    Secondary data
Correct answer is option 'C'. Can you explain this answer?

Primary Data in Statistics

Primary data is the data that is collected firsthand by the researcher himself for a specific research purpose. It is original data that has not been processed or analyzed by anyone else. The researcher collects primary data by conducting surveys, experiments, observations, or interviews.

Explanation:

In the given scenario, a student collects information about the number of school going children in a locality consisting of a hundred households. This information is collected by the student himself for a specific research purpose, making it primary data. The data is collected through surveys or interviews conducted by the student.

Option C is the correct answer as it refers to primary data. Option A, arrayed data, refers to data that is arranged in a specific sequence or order. Option B, grouped data, refers to data that is organized into groups or categories for analysis. Option D, secondary data, refers to data that has already been collected and processed by someone else for a different research purpose.

A set of data consists of six numbers: 7, 8, 8, 9, 9 and x. The difference between the modes when x = 9 and x = 8 is
  • a)
    1
  • b)
    4
  • c)
    3
  • d)
    2
Correct answer is option 'A'. Can you explain this answer?

Dhwani Shah answered
**Solution:**

To find the difference between the modes when x = 9 and x = 8, we need to determine the modes for both scenarios and then calculate the difference between them.

Given data set: 7, 8, 8, 9, 9, x

**When x = 9:**

In this case, the data set becomes: 7, 8, 8, 9, 9, 9

The modes are the numbers that appear most frequently in the data set. In this case, the modes are 8 and 9, as they both appear twice.

**When x = 8:**

In this case, the data set becomes: 7, 8, 8, 9, 9, 8

The modes are the numbers that appear most frequently in the data set. In this case, the modes are 8 and 9, as they both appear twice.

Therefore, the modes are the same for both scenarios: 8 and 9.

**Calculating the difference between the modes:**

To calculate the difference between the modes, we subtract the smaller mode from the larger mode.

In this case, the smaller mode is 8 and the larger mode is 9.

Difference = 9 - 8 = 1

Therefore, the difference between the modes when x = 9 and x = 8 is 1.

Hence, the correct answer is option A.

The quantitative character of an item is shown by
  • a)
    attributes.
  • b)
    variables.
  • c)
    figures.
  • d)
    tables.
Correct answer is option 'B'. Can you explain this answer?

Poonam Reddy answered
Heights and weights of individuals are variables as they can be measured in numerical terms. Thus, variables are used when changing characterstics are numerically measured.

In a bar graph, 0.25 cm length of a bar represents 100 people. Then, the length of bar which represents 2000 people is
  • a)
    4 cm
  • b)
    4.5 cm
  • c)
    5 cm
  • d)
    3.5 cm
Correct answer is option 'C'. Can you explain this answer?

Vikram Khanna answered
To find the length of a bar that represents 2000 people in a bar graph, you can use the following steps:
Identify the scale of the bar graph: In this case, the scale of the bar graph is 0.25 cm per 100 people.
Calculate the number of units on the scale: To find the number of units on the scale, you can divide the number of people by the number of people per unit. In this case, you would divide 2000 people by 100 people/unit = 20 units.
Multiply the number of units by the length of each unit: To find the length of the bar, you can multiply the number of units by the length of each unit. In this case, the length of the bar would be 20 units * 0.25 cm/unit = 5 cm.
Therefore, the length of a bar that represents 2000 people in this bar graph is 5 cm. The correct answer is option (c).

In a bar graph, 0.25 cm length of a bar represents 100 people. Then, the length of bar which represents 2000 people is
  • a)
    5 cm
  • b)
    4 cm
  • c)
    4.5 cm
  • d)
    3.5 cm
Correct answer is option 'A'. Can you explain this answer?

Charvi Tiwari answered
Given, 0.25 cm represents 100 people.

To find the length of the bar that represents 2000 people, we need to use the concept of proportionality.

Let x be the length of the bar that represents 2000 people.

We know that,

0.25 cm represents 100 people

So,

x cm represents 2000 people

Using the concept of proportionality, we can write:

0.25/100 = x/2000

Simplifying the above equation, we get:

x = (0.25 x 2000)/100

x = 5 cm

Therefore, the length of the bar that represents 2000 people is 5 cm.

Hence, the correct option is (a) 5 cm.

The mathematical average is also called
  • a)
    median.
  • b)
    mode.
  • c)
    mean.
  • d)
    quartile.
Correct answer is option 'C'. Can you explain this answer?

Tejas Verma answered
► Mean is a mathematical average.
The arithmetic mean or mean is defined as the sum of values of a group of items divided by the number of items. It is denoted by mean.

Each given interval is called a
  • a)
    frequency.
  • b)
    series.
  • c)
    class.
  • d)
    distribution.
Correct answer is option 'C'. Can you explain this answer?

Poonam Reddy answered
Difference between upper and lower class limit is called class interval.
For example, 0-10, 10-20, 20-30 etc.

To analyse the election results, the data is collected from a newspapers. The data thus collected is known as
  • a)
    secondary data
  • b)
    raw data
  • c)
    grouped data
  • d)
    primary data
Correct answer is option 'A'. Can you explain this answer?

Analyzing Election Results through Secondary Data

Introduction
Election results are crucial in determining the political landscape of a country or region. To analyze these results, data is collected from various sources, including newspapers. The data collected from newspapers is known as secondary data.

What is Secondary Data?
Secondary data is information that has already been collected by someone else for a different purpose and is being reused for another research project. It is collected from various sources, such as newspapers, government reports, online databases, and academic journals.

Why Use Secondary Data?
There are several reasons why researchers use secondary data:

- It is cost-effective as the data is already available, and there is no need to spend money on data collection.
- It saves time as the data is readily available.
- It can be used to replicate previous studies, compare results, and test hypotheses.
- It provides a broader perspective as data from different sources can be analyzed.

Advantages of Using Secondary Data for Election Analysis
Using secondary data to analyze election results has several advantages:

- The data is already available, saving time and resources.
- It provides a broader perspective as data from different sources can be collected and analyzed.
- It enables researchers to compare results from different elections and regions.
- It can be used to replicate previous studies and test hypotheses.

Disadvantages of Using Secondary Data for Election Analysis
Using secondary data to analyze election results also has some disadvantages:

- The data may not be accurate, complete, or up-to-date.
- The data may not be available in the required format for analysis.
- The data may be biased towards certain political parties or regions.
- The data may not be representative of the entire population.

Conclusion
In conclusion, analyzing election results through secondary data collected from newspapers is a cost-effective and time-saving way to gain a broader perspective on the political landscape. However, researchers should be aware of the limitations and biases of the data and use it with caution.

The mean of first four prime numbers is
  • a)
    4
  • b)
    4.5
  • c)
    3.75
  • d)
    4.25
Correct answer is option 'D'. Can you explain this answer?

Sarthak Satav answered
First four prime number 2,3,5,7
mean = sum of all observation/Number of observation
= 2+3+5+7 / 4
= 17/4
= 4.25
so option D is correct

In a frequency distribution, the mid-value of a class is 60.5 and the width of the class is 10. The lower limit of the class is
  • a)
    55.5
  • b)
    56.5
  • c)
    62.5
  • d)
    65.5
Correct answer is option 'A'. Can you explain this answer?

Arpita Rane answered
To find the lower limit of the class, we can subtract half of the width of the class from the mid-value of the class.

Given information:
Mid-value of the class = 60.5
Width of the class = 10

Finding the lower limit of the class:
Lower limit of the class = Mid-value of the class - (Width of the class / 2)

Substituting the given values:
Lower limit of the class = 60.5 - (10 / 2)

Simplifying the expression:
Lower limit of the class = 60.5 - 5

Therefore, the lower limit of the class is 55.5.

So, the correct answer is option 'A' (55.5).

The subject that helps in analysing economic problems and formulating policies to solve them is
  • a)
    Physics.
  • b)
    Chemistry
  • c)
    Mathematics.
  • d)
    Statistics.
Correct answer is option 'D'. Can you explain this answer?

Sanjeev Kumar answered
Statistics helps in analysing economic problems and formulating policies to solve them. Statistics is the study of aggregate of facts numerically expressed.

The mean of six numbers is 23. If one of the numbers is excluded, the mean of the remaining numbers becomes 20. The excluded number is
  • a)
    38
  • b)
    37
  • c)
    36
  • d)
    39
Correct answer is option 'A'. Can you explain this answer?

Soumya Tiwari answered
To solve this problem, we need to use the concept of the mean and how it is affected by adding or removing numbers from a set of data. Let's break down the given information and solve the problem step by step.

Given Information:
- The mean of six numbers is 23.
- If one of the numbers is excluded, the mean of the remaining numbers becomes 20.

Step 1: Find the sum of the six numbers
Since the mean is the sum of all numbers divided by the total count, we can find the sum of the six numbers by multiplying the mean (23) by the count (6).
Sum of the six numbers = Mean * Count = 23 * 6 = 138

Step 2: Find the sum of the five remaining numbers
If the mean of the remaining five numbers is 20, we can find the sum of those numbers by multiplying the mean (20) by the count (5).
Sum of the five remaining numbers = Mean * Count = 20 * 5 = 100

Step 3: Find the excluded number
To find the excluded number, we need to subtract the sum of the five remaining numbers from the sum of the six numbers.
Excluded number = Sum of the six numbers - Sum of the five remaining numbers = 138 - 100 = 38

Conclusion:
The excluded number is 38 (option A) based on the given information and calculations above.

There are 50 numbers. Each number is subtracted from 53 and the mean of the numbers so obtained is found to be – 3.5. The mean of the given number is
  • a)
    47.5
  • b)
    52.5
  • c)
    56.5
  • d)
    49.5
Correct answer is option 'C'. Can you explain this answer?

Hansa Sharma answered
Total numbers =50
Mean of numbers after subtracting 53 from each =3.5
Sum of numbers after subtracting 53 from each =3.5×50=175
Sum of the original numbers =175+53×50=2825

Mean of the original numbers =2825/50​=56.5

In a grouped frequency distribution, the class intervals are 0-10, 10-20, 20-30, .., then the class width is
  • a)
    10
  • b)
    15
  • c)
    20
  • d)
    30
Correct answer is option 'A'. Can you explain this answer?

Sara Nair answered
Explanation:

A grouped frequency distribution is a tabular representation of data that is divided into intervals or classes, and each class represents a range of values. In this case, the class intervals are 0-10, 10-20, 20-30, and so on.

The class width is the difference between the upper and lower class limits of a class interval. In this case, the lower class limit of the first interval is 0 and the upper class limit is 10. Therefore, the class width is:

Upper class limit - Lower class limit = 10 - 0 = 10

Hence, the correct answer is option A) 10.

A self-addressed and stamped envelope should be enclosed with a questionnaire is called
  • a)
    offer letter
  • b)
    appointment letter
  • c)
    covering letter
  • d)
    resignation letter
Correct answer is option 'C'. Can you explain this answer?

A cover letter accompanies or transmits another document such as a survey questionnaire. Its purpose is to alert the respondent about the questionnaire it accompanies and to provide the details of requested actions on the part of the respondent. A cover letter is a living document that often accompanies a resume.

Statistical data can be presented in
  • a)
    one form.
  • b)
    two forms.
  • c)
    three forms.
  • d)
    four forms.
Correct answer is option 'C'. Can you explain this answer?

Statistical data can be presented in three forms namely, tabular presentation, diagrammatic presentation and graphic presentation.

Arrangement of data into different groups is known as
  • a)
    collection of data
  • b)
    presentation of data.
  • c)
    pictograph
  • d)
    classification
Correct answer is option 'D'. Can you explain this answer?

Om Desai answered
Classification is the process of arranging things (either actually or notionally) in the groups according to their resemblances and affinities and gives expression to the unity of attributes that may subsist amongst a diversity of individuals.

Let x be the mean of squares of first n natural numbers and y be the square of mean of first n natural numbers. If x/y = 55/42, then what is the value of n ?
  • a)
    24
  • b)
    25
  • c)
    27
  • d)
    30
Correct answer is option 'C'. Can you explain this answer?

Tejas Desai answered
Given:
Let x be the mean of squares of the first n natural numbers.
Let y be the square of the mean of the first n natural numbers.
It is given that x/y = 55/42.

To Find:
The value of n.

Explanation:
Let's start by finding the values of x and y.

Finding the value of x:
The squares of the first n natural numbers are 1^2, 2^2, 3^2, ..., n^2.
The sum of these squares can be expressed as:
x = 1^2 + 2^2 + 3^2 + ... + n^2

Using the formula for the sum of squares, we can rewrite this as:
x = n(n + 1)(2n + 1)/6

Finding the value of y:
The mean of the first n natural numbers is the sum of the numbers divided by n.
The sum of the first n natural numbers can be expressed as:
sum = 1 + 2 + 3 + ... + n

Using the formula for the sum of an arithmetic series, we can rewrite this as:
sum = n(n + 1)/2

The mean is sum/n, so we can write the mean as:
mean = n(n + 1)/2n = (n + 1)/2

The square of the mean is:
y = (mean)^2 = [(n + 1)/2]^2 = (n + 1)^2/4

Calculating x/y:
Now, we can calculate x/y using the values we found for x and y:
x/y = (n(n + 1)(2n + 1)/6) / ((n + 1)^2/4)
Simplifying this expression:
x/y = (4n(n + 1)(2n + 1)) / (6(n + 1)^2)
x/y = (4n(2n + 1)) / (6(n + 1))
x/y = (2n(2n + 1)) / (3(n + 1))

Given that x/y = 55/42, we can set up the equation:
(2n(2n + 1)) / (3(n + 1)) = 55/42

Solving the equation:
Cross multiplying:
42 * 2n(2n + 1) = 55 * 3(n + 1)
84n(2n + 1) = 165(n + 1)
168n^2 + 84n = 165n + 165
168n^2 - 81n - 165 = 0

Factoring the quadratic equation:
(8n - 11)(21n + 15) = 0

Setting each factor to zero and solving for n:
8n - 11 = 0 or 21n + 15 = 0
8n = 11 or 21n = -15
n = 11/8 or n = -15/21

Since n represents the number of natural numbers, it cannot be negative. Therefore, n = 11/8 is not a valid solution.

Conclusion:
The valid solution for n

Find the value ‘p + q’, if mean of set of numbers 3, 6, 7, 14, p, 34, 26, q, 12 is given as 22.
  • a)
    96
  • b)
    88
  • c)
    76
  • d)
    75
Correct answer is option 'A'. Can you explain this answer?

Nishtha Bose answered
Understanding the Problem
To find the value of 'p + q' given the mean of the numbers, we first need to understand the concept of mean. The mean is calculated by dividing the sum of all numbers by the total count of those numbers.
Given Data
We have the numbers: 3, 6, 7, 14, p, 34, 26, q, 12.
- Total Count of Numbers = 9
- Given Mean = 22
Calculating the Total Sum
The formula for mean can be expressed as:
\[
\text{Mean} = \frac{\text{Sum of all numbers}}{\text{Total count of numbers}}
\]
Substituting the known values:
\[
22 = \frac{3 + 6 + 7 + 14 + p + 34 + 26 + q + 12}{9}
\]
Now, we multiply both sides by 9 to isolate the sum:
\[
22 \times 9 = 3 + 6 + 7 + 14 + p + 34 + 26 + q + 12
\]
Calculating the left side:
\[
198 = 3 + 6 + 7 + 14 + p + 34 + 26 + q + 12
\]
Calculating the Known Sum
Now, let's sum the known numbers:
\[
3 + 6 + 7 + 14 + 34 + 26 + 12 = 102
\]
Substituting this back into the equation:
\[
198 = 102 + p + q
\]
Finding p + q
Now, we can solve for \( p + q \):
\[
p + q = 198 - 102 = 96
\]
Conclusion
Thus, the value of \( p + q \) is 96. Hence, the correct answer is option 'A'.

The range of the data 20, 8, 20, 18, 16, 15, 30, 12, 22, 6, 11, 17, 25, 32, 10, 19 is
  • a)
    15
  • b)
    16
  • c)
    18
  • d)
    26
Correct answer is option 'D'. Can you explain this answer?

Sara Khanna answered
Given data:
The given data is: 20, 8, 20, 18, 16, 15, 30, 12, 22, 6, 11, 17, 25, 32, 10, 19.

Range of data:
The range of data is the difference between the maximum and minimum values in a dataset. To find the range of the given data, we need to determine the maximum and minimum values first.

Finding the maximum and minimum values:
To find the maximum and minimum values in the given data, we can arrange the data in ascending order. This gives us: 6, 8, 10, 11, 12, 15, 16, 17, 18, 19, 20, 20, 22, 25, 30, 32.

- The minimum value is 6 (the first number in the arranged data).
- The maximum value is 32 (the last number in the arranged data).

Calculating the range:
The range is calculated by subtracting the minimum value from the maximum value.

Range = Maximum value - Minimum value
Range = 32 - 6
Range = 26

Therefore, the range of the given data is 26.

Final answer:
The correct answer is option D) 26.

Given the class intervals 1-10, 11-20, 21-30, …, then 20 is considered in class
  • a)
    11-30
  • b)
    11-20
  • c)
    21-30
  • d)
    15-25
Correct answer is option 'B'. Can you explain this answer?

Sankar Kaur answered
And so on, what is the midpoint of the class interval 31-40?

The midpoint of a class interval is found by adding the lower and upper limits of the interval and dividing by 2.

For the interval 31-40, the lower limit is 31 and the upper limit is 40.

Midpoint = (31 + 40) / 2 = 71 / 2 = 35.5

Therefore, the midpoint of the class interval 31-40 is 35.5.

Out of sixteen observations arranged in an ascending order, the 8th and 9th observations are 25 and 27. Then, the median is
  • a)
    26
  • b)
    27
  • c)
    25
  • d)
    26.5
Correct answer is option 'A'. Can you explain this answer?

Pranjal Gupta answered
To find the median, we need to determine the middle value of the observations. In this case, we have 16 observations arranged in ascending order.

Given that the 8th observation is 25 and the 9th observation is 27, we can see that these two values are consecutive. This means that there are 7 observations before the 8th observation (including the 8th observation itself) and 6 observations after the 9th observation (including the 9th observation itself).

Since there are an even number of observations (16), the median will be the average of the two middle values. In this case, the two middle values are the 8th and 9th observations, which are 25 and 27.

To find the average, we add the two values together and divide by 2:
(25 + 27) / 2 = 52 / 2 = 26.

Therefore, the median of the given observations is 26.

Hence, the correct answer is option A) 26.

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