# 90%, 95%, and 99% confidence intervals. Business research methods

A random sample of 100 students attending a concert spent an average of \$142 on their tickets with a standard deviation of \$47.50.
Calculate the 90%, 95%, and 99% confidence intervals for the mean amount of money spent by all students attending the concert. Interpret your response within the context of the situation. Refer to Chapter 17, pp. 427-430 on calculating confidence intervals. Click here for Table A.2 from the appendix.
Keri is the owner of a new restaurant in the downtown area of her hometown. To continuously improve service, she would like to know if completed dishes are being delivered to the customer?s table within one minute of being completed by the chef. A random sample of 75 completed dishes showed that 60 were delivered within one minute of completion.
Calculate the 90%, 95%, and 99% confidence interval for the true population proportion. Interpret your response within the context of the situation. Refer to Chapter 17, pp. 427-430 on calculating confidence intervals. Click here for Table A.2 from the appendix.