II. SHORT ANSWER TYPE QUESTIONS
Q1. Find the mode of the data:
Marks  010  1020  2030  3040  4050 
No. of students  3  12  32  20  6 
Sol. Here, modal class is 20–30
f_{1} = 32, f_{2} = 20 and f_{0} = 12
Since, the lower limit of the modal class
l = 20
[∵ h = 10]
Q2. The percentage marks obtained by 100 students in an examination are given below:
Marks  3035  3540  4045  4550  5055  5560  6065 
Frequency  10  16  18  23  18  8  7 
Find the median from the above data.
Sol. We have:
Marks  Frequency  cf 
3035  10  10 + 0 = 10 
3540  16  16 + 10 = 26 
4045  18  18 + 26 = 44 
4550  23  23 + 44 = 67 
5055  18  18 + 67 = 85 
5560  8  8 + 85 = 93 
6065  7  7 + 93 = 100 
Here,
∴ The median class is 45−50, such that
l = 45, cf = 44, f = 23 and h = 5
Q3. Write a frequency distribution table for the following data:
Marks  Above 0  Above 10  Above 20  Above 30  Above 40  Above 50 
No. of students  30  28  21  15  10  0 
Sol. Since,
30 − 28 = 2
28 − 21 = 7
21 − 15 = 6
15 − 10 = 5
10 − 0 =10
The required frequency distribution is:
Marks  Number of students 
010  2 
1020  7 
2030  6 
3040  5 
4050  10 
Total  30 
Q4. Find the median of the following data:
Class interval  020  2040  4060  6080  80100  100120 
Frequency  7  8  12  10  8  5 
Sol.
Class Interval  Frequency  Cumulative frequency 
020  7  7 
2040  8  15 
4060  12  27 
6080  10  37 
80100  8  45 
100120  5  50 
Total  50 

∵ Median class is 40–60
∴ l = 40, f = 12, CF = 15 and h = 20
Since,
124 videos457 docs77 tests

1. What is statistics? 
2. What are the different types of data in statistics? 
3. How do you calculate the mean, median, and mode? 
4. What is the difference between correlation and causation? 
5. How can statistics be used in real life? 

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