A bank manager wanted to double-check her claim that recent process improvements have reduced customer wait times to an average of 3.4 minutes, with a standard deviation of 0.9 minutes. To test this, she randomly sampled 25 customers and recorded their wait times. The average wait time of the customers in the sample was 3.9 minutes. Assuming the claim about wait time is true, what is the probability that a random sample of nequals25 customers would have a sample mean as large as or greater than 3.9 minutes? What should the manager conclude about her claim?

P(x overbargreater than or equals3.9)equals

nothing (Round to four decimal places as needed.)

What conclusion should the manager draw about her claim of improved service times?

A. The manager is overestimating wait times.

B. The customers are overestimating wait times.

C. The manager is underestimating wait times.

D. The manager is accurately estimating wait times.