1.What it is the average cost of a movie ticket. If you assume that the population standard deviation is $0.75, what sample size would you need to be 95% confident that your estimate was within $0.25 of the true mean ticket prices?

2.Some people who bought a certain gaming system complained about having received a defective console. In a sample of 120 units sold, 6 units were defective.

a) Compute the standard error of the proportion.

b)Determine a 95% confidence interval for the percentage of defective systems.

3. You are given the following dataobtained from a sample of 6 observations taken from a population that has a normal distribution.Develop an 80% confidence interval estimate for the mean of the population.

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4.A sales manager is reviewing his sales team's record of sales during August.After examining his records from the past 10 years, he finds that the number of sales each August have a mean of 76 and a standard deviation of 12.The sales manager offers his team of 36 an extra week of vacation if the sales average is above 80 for this August.What is the probability that he will have to deliver on his promise?

5.The human resource director of a large corporation wishes to study absenteeism among its mid-level managers at its central office during the year.

a) A study of a random sample of 25 mid-level managers reveals that the mean number of days absent is 6.2 days, with the sample standard deviation equal to 7.3 days.Construct a 95% confidence interval for the mean number of absences for mid-level managers during the year.

b) That same study of a random sample of 25 mid-level managers also reveals that 13 of the 25 mid-level managers cite stress as a cause of absence.Construct a 95% confidence interval estimate for the population proportion of mid-level managers who cite stress as a cause of absence.

Suppose that the HR director wishes to administer a survey in one of its regional offices.Answer these questions:

c) What sample size is needed to have 95% confidence in estimating the population mean absenteeism to within 1.5 days, if the population standard deviation is estimated to be 8 days?

d) How many mid-level managers need to be selected to have 90% confidence in estimating the population proportion of mid-level managers who cite stress as a cause of absence to within 0.075 if no previous estimate is available?

e) Based on c and d answers above, what sample size is needed if a single survey is being conducted?