Question

1.One of the relatively uncommon instances in which researchers know the population standard deviation is in the case of the Intelligence Quotient or IQ test. In general, the average IQ score in large, diverse populations is 100 and the standard deviation is 15. Suppose that your sample of 300 members of your community gives you a mean IQ score of 108. Calculate a 90% confidence interval for the mean and indicate which answers come closest to those that would fill the blanks in the following interpretation: we can be 90% confident that they mean IQ score in this community lies between _____ and _____ .

2.Suppose that you are a city planner who obtains and sample of 20 randomly selected members of a mid-sized town in order to determine the average amount of money that residents spend on transportation each month (such as fuel, vehicle repairs, and public transit). You do not have the population standard deviation. To 3 decimal places, what is the critical value for the 95% confidence interval? In the same scenario as 7.09, suppose you obtained a mean of $167 spent on transportation and a standard deviation of $40. Calculate a 95% confidence interval for the mean and select the values that come closest to those that would fill the spaces in the following interpretation: we can be 95% confident that they mean amount of money spent on transportation lies between _____ and _____ .

Answer 1