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. must be at least zero b. is negative since all the numbers are negative c. cannot be computed since all the numbers are negative. d. can be either negative or positive.

The variance of the temperatures of the 10 day period must be at least zero.

Step-by-step explanation:

The variance is the expectation of the squared deviation of a random variable from its mean. It measures how far a set of numbers are spread out from their average value.

Its unit of measure corresponding to the square of the unit of measure of the variable. In this case, the variance of the temperatures is expressed in (°C)². The variance has a minimum value of 0.

Since the variance is squared, it will always have values greater than zero.

21

step-by-step explanation:

341

step-by-step explanation:

all you have to do is 9x31 (which equals 279) and then 20x31 (which equals 620). then you have to subtract. 620-279=341.