Exam 7: Sampling Distributions

SCENARIO 7-5 According to an article, 19% of the entire population in a developing country has high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Scenario 7-5, the population mean of all the sample proportions is _.

As the sample size increases, the standard error of the mean increases.

SCENARIO 7-6 Online customer service is a key element to successful online retailing.According to a marketing survey, 37.5% of online customers take advantage of the online customer service.Random samples of 200 customers are selected. -Referring to Scenario 7-6, the population mean of all possible sample proportions is .

Sales prices of baseball cards from the 1960s are known to possess a right skewed distribution with a mean sale price of $5.25 and a standard deviation of $2.80.Suppose a random sample of100 cards from the 1960s is selected.Describe the sampling distribution for the sample mean sale price of the selected cards.

SCENARIO 7-6 Online customer service is a key element to successful online retailing.According to a marketing survey, 37.5% of online customers take advantage of the online customer service.Random samples of 200 customers are selected. -Referring to Scenario 7-6, % of the samples are likely to have less than 37.5% who take advantage of online customer service.

SCENARIO 7-5 According to an article, 19% of the entire population in a developing country has high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Scenario 7-5, among all the random samples of size 200, % will have more than 30% who have high-speed access to the Internet.

The distribution of the number of loaves of bread sold per week by a large bakery over the past 5 years has a mean of 7,750 and a standard deviation of 145 loaves.Suppose a random sample ofn = 40 weeks has been selected.What is the approximate probability that the mean number ofloaves sold in the sampled weeks exceeds 7,895 loaves?