Customers often complain about long waiting times at restaurants before the food is served. A restaurant claims that it serves food to its customers, on average, within 15.5 minutes after the order is placed. A local newspaper journalist wanted to check if the restaurant's claim is true. A sample of 35 customers showed that the mean time taken to serve food to them was 16.1 minutes with a standard deviation of 2.8 minutes. Using the sample mean, the journalist says that the restaurant's claim is false. Do you think the journalist's conclusion isfair to the restaurant? Use a 0.5% significance level to answer this question.

a) State the Null and Alternate Hypotheses

b) Which is the claim?

c) Will you use a ztest, ttest or chisquare test? What is the critical value?

d) Describe the reject region as left tailed, right

tailed or twotailed and find the sample statistics.

f) Do you reject the claim? Write out your decision

in at least one sentence

10.

Home Mail Corporation sells products by mail. The company's management wants to find out if the number of orders received at the company's office on each of the five days of the week is the same. The company took a sample of 400 orders received during a four-week period. The following table lists the frequency distribution for these orders by the day of the week.

Day of the

week

MON TUE WED THU FRI 92 71 65 83 89

Number of

orders received

Test at a 5% significance level whether we can reject the null hypothesis that the orders are evenly distributed over all days of the week.

a) State the Null and Alternate Hypotheses b) Which is the claim? c) Will you use a ztest, ttest or chisquare test? What is

the critical value? d) Describe the reject region as left tailed, right tailed or

twotailed and find the sample statistics.

e) Do you reject the claim? Write out your decision in at least one sentence