Important Formula: Elementary Statistics | Mathematics for RRB NTPC / ASM - RRB NTPC/ASM/CA/TA PDF Download

Statistics is a branch of mathematics that deal with the collection, organization, presentation, analysis and interpretation of data.In simple words statistics deals with data. On this page we’ll look fro some of the Formulas for Elementary Statistics to make your calculations easier and rapid.

There are four measures of dispersion.These can be written as:

• Range
• Mean deviation
• Variance
• Standard deviation

Formulas for Elementary Statistics

(1) Mean=KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
N=Total number of terms

(2) Mode=M=The value which occurs most frequently

(3) Mean Deviation,M.D.=KaTeX parse error: KaTeX doesn't work in quirks mode. (from average deviation)

(4) Variance, KaTeX parse error: KaTeX doesn't work in quirks mode.

(5) Standard deviation,KaTeX parse error: KaTeX doesn't work in quirks mode.
= KaTeX parse error: KaTeX doesn't work in quirks mode.

More About Elementary Statistics Term

Mean can  be defined as the sum of all the elements divided by number of all elements.

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Median: Median is defined as the middle value of a set of data. If a set consists of an odd number of values, then the middle value will be the median of the set.Else, if the set consists of an even number of sets, then the median will be the average of the two middle values.

Mode: The mode can be defined as the most frequent value in the given set of data.

Variance: Variance is used to calculate the standard deviation.It is always positive.

Standard deviation: It is the square root of the variance.

Examples

Consider the data set containing the values 20, 24, 25, 36, 25, 22, 23.

Example 1:  Find the mean of the data.
Sol: We know that,
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Mean=KaTeX parse error: KaTeX doesn't work in quirks mode.
=25

Example 2: Calculate the mode for the above data.
Sol: The mode can be defined as the most frequent value in the given set of data.In the data given the most frequent value is 25 which occurred more than any other value.Hence the mode is 25.