If 5 is added to each and every item of a data, then the arithmetic mean is A) 5 times to the first arithmetic mean
If 5 is added to each and every item of a data, then the arithmetic mean is
A) 5 times to the first arithmetic mean
B) increased by 5 to the first arithmetic mean
C) equal to the first arithmetic mean
D) None
2 Answers
Correct option is: B) increased by 5 to the first arithmetic mean
Let \(x_i\) be the original observations of the data.
Let there are total n number of observations in the data.
\(\therefore\) Sum of original observation = n \(\times\) original mean
\(\Rightarrow\) \(\sum x_i = n\overline x\) , where \(\overline x\) is original mean of data.
Since, 5 is added to each and every item of the data.
\(\therefore\) Each observations of new data is of type (\(x_i+5\)).
\(\therefore\) Sum of new observations = \(\sum x_i+5\)
\(\therefore\) New mean = \(\frac {\sum x_i+5}n = \frac {\sum x_i+\sum5}n\)
= \(\frac {n\overline x + 5n}{n} = \frac {n(\overline x+5)}n = \overline x+5\)
Hence, the new arithmetic mean is increased by 5 to the first arithmetic mean.