Question

The standard deviation of $15$ terms is $6$ and each item is decreased by $1$. Then the standard deviation of new data is?

• A. $5$
• B. $7$
• C. $\frac{91}{15}$
• D. $6$

Answer 1

The correct option is D $6$

If each term of the data set is increased or decreased by the same amount, the standard deviation remains unchanged.

$\therefore$ Standard deviation of the new data set is also 6.
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