During a cold winter, the temperature stayed below zero for 10 days (ranging from -20 to -5). The variance of the temperatures of the 10 day period _____.
A) is negative since all the numbers are negative
B) must be at least zero
C) cannot be computed since all the numbers are negative
D) can be either negative or positive

Question

Quizplus · Accepted Answer

The variance is a measure of how spread out the data is from its mean. It is always non-negative because it involves squaring the differences from the mean. Even though temperatures are negative in this case, squaring them will make them positive. Therefore, the variance of the temperatures of the 10 day period must be at least zero.

During a Cold Winter, the Temperature Stayed Below Zero for 10