7)

8.2 Confidence Interval for Mean A farmer wants to know the mean weight of the apples on his orchard. He picks 80 apples which have an average weight of 142.2 ounces. Assume the population weights are normally distributed and the population standard deviation is 2.5 ounces. What is the 95% confidence interval for mean weight of the apples? a.) Which distribution table will be used to find the critical value and why?

• Z-table because the population standard deviation is known
• Z-table because the population standard deviation is unknown
• t-table because the population standard deviation is unknown
• t-table because the population standard deviation is known

b.) With 95% confidence, we can say the true population mean weight of the apples is between ** and ** ounces.