Question

HEB tracks the efficiency of its pharmacists in filling orders. Let T be the time in minutes to fill a randomly selected order. Here is the probability distribution for T.

T (time in minutes)	Probability
1	0.03
2	0.24
3	0.31
4	0.16
5

This table is missing the P(T = 5 minutes). Your first step is to calculate this probability.

Next, calculate the population mean. (Careful! This mean is NOT the same as the sample mean.)

Finally, calculate the population variance. (Careful! This variance is NOT the same as the sample variance.)

Enter your answer for the population variance to 2 decimal places of accuracy.

Answer 1

Conditions for the discrete probability distribution

The sum of all probability is equal to 1.

1	0.03	0.03	1	0.03
2	0.24	0.48	4	0.96
3	0.31	0.93	9	2.79
4	0.16	0.64	16	2.56
5	0.26	1.3	25	6.5