Following are the closing prices (in dollars) of a certain stock for the past 20 trading days.
$\begin{array}{llllllllll}
\hline 153.21 & 151.33 & 155.74 & 147.55 & 123.45 & 151.24 & 145.02 & 127.33 & 157.17 & 125.64 \
\hline 145.78 & 142.76 & 125.17 & 126.34 & 153.05 & 130.41 & 141.26 & 137.18 & 147.74 & 147.19 \
\hline
\end{array}$
Find the population standard deviation for the closing prices.
A) $11.39
B) $33.72
C) $141.73
D) $11.10

Question

Quizplus · Accepted Answer

To find the population standard deviation, first calculate the mean (average) of the closing prices, then use the formula for the population standard deviation, which involves squaring the difference between each value and the mean, summing those squared differences, dividing by the number of observations, and finally taking the square root of that result. The correct calculation leads to a population standard deviation of approximately $11.10, not the other values listed.

Following Are the Closing Prices (In Dollars) of a Certain