1. A produce manager wants to estimate the mean weight of Spanish onions being delivered by a supplier, with a 95% confidence level and an error of +/- 0.8 ounce. A preliminary sample of 15 onions shows a sample standard deviation of 3.5 ounces. How many Spanish onions must be sampled to estimate the population mean weight within +/- 0.8 ounce? (Use z=1.96.)

1. A sample of 65 retail in-store purchases showed that 24 were paid in cash. Calculate and interpret a 99% confidence interval for the true proportion of all in-store purchases that are cash transactions.

1. A survey showed that 5.8% of 300 Americans surveyed had suffered some kind of identity theft in the past year.
   1. Calculate and interpret a 99% confidence interval for the true proportion of Americans who have suffered some kind of identity theft in the past year.
   2. Are the necessary assumptions met? Explain why or why not.