Opre homework 3

question 21

A local hotel wants to estimate the average age of its guests that are from out-of-state. Preliminary estimates are that the standard deviation of population of guests from out-of-state is 30. How large a sample should be taken to estimate the average age of out-of-state guests with a margin of error no larger than 5 and with a 95% level of confidence? O a. 12 O b. 11 O c. 138 O d. 139Question 21 Six hundred consumers were asked whether they would like to purchase a domestic or a foreign automobile. Their responses are given below. Preference Frequency Domestic 240 Foreign 360 Develop a 95% confidence interval for the proportion of all consumers who prefer to purchase domestic automobiles Page 5 O a. 0.504 to 0.696 O b.0.234 to 0.516 O c. 0.199 to 0.261 O d.0.3608 to 0.4392A major electronics store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. It is known that the amount spent by the credit card customers on their first visit to the chain's new store is normally distributed. Fifteen credit card accounts were randomly sampled and analyzed with the following results: sample average spending of x= $50.50 and sample standard deviation of S - 20. A 95% confidence interval for the average amount the credit card customers spent on their first visit to the chain's new store in the mall is: O a. $50.50 + $9.09 O b. $50.50 + $10.12 O c. $50.50 + $11.08 O d. None of these choicesA social researcher claims that the average adult listens to the radio less than 26 hours per week. He collects data on 25 individuals' dadio listening habits and finds that the mean number of hours that the 25 people spent listening to the radio was 22.4 hours. If the population standard deviation is known to be eight hours, can we conclude at the 1% significance level that he is right? O a. We can conclude at a = .01 that the social researcher is right O b. We cannot conclude at a =.01 that the social researcher is right O c. We cannot make a decision based on the given information O d. None of the above