a) At least 3 of them fail the Psychology test
b) Exactly 4 of them pass the Psychology test

4.
(7 points) The number of animal crackers that an individual can eat is shown
in the table below, with the corresponding probabilities.
Find the mean,
variance, and standard deviation.
Show your work to receive credit.
Number of Animal
Crackers
Individual Can Eat
6
10
14
18
22
26
Probability
0.21
0.15
0.18
0.24
0.16
0.06