# statistic

posted by
**Nancy**
.

The amount of time a bank teller spends with each customer has a population

mean of 3.10 minutes and standard deviation of 0.40 minute. If a random sample

of 16 customers is selected,

a) what assumption must be made in order to solve parts (b) and (c)?

b) what is the probability that the average time spent per customer will be at

least 3 minutes?

c) there is an 85% chance that the sample mean will be below how many

minutes?

d) If a random sample of 64 customers is selected, there is an 85% chance that

the sample mean will be below how many minutes?