1a)The company randomly selects a number of registered customers. It calls these customers asking them to complete a customer satisfaction survey by phone. From previous surveys, the company knows that the chance of a selected customer agreeing to complete the survey is 20%. If in one day it calls 14 selected customers, what is the chance that exactly 4 customers complete the survey?

b) What assumptions did you need to make to answer c.? Answer in relation to this particular situation.

2) The company has a complaints telephone line. The company is concerned that because of changes to their website, more lengthy complaints calls are being received. A sample of 100 calls is taken. Their average is 7.25 minutes. The population mean is known to have been 7 minutes with a standard deviation of 2.1 minutes. Use a hypothesis test to test if the mean call time has changed from 7 minutes at the 1% level of significance. Show all steps (hypotheses, test statistic, decision rule) and explain your conclusion.

*Please show steps for all calculations