Author Question: Suppose that the amount of time teenagers spend on the internet is normally distributed with a ... (Read 127 times)

xclash · **on:** Jun 24, 2018

Suppose that the amount of time teenagers spend on the internet is normally distributed with a standard deviation of 1.5 hours. A sample of 100 teenagers is selected at random, and the sample mean computed as 6.5 hours. A) Determine the 95 confidence interval estimate of the population mean. ___________________ _ to ___________________ _ B) Interpret what the interval estimate in part (a) tells you.
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Question 2

There are 300 students enrolled in Business Statistics. Historically, exam scores are normally distributed with a standard deviation of 30.9 . Your instructor randomly selected a sample of 30 examinations and finds a mean of 74.2 . Determine a 90 confidence interval for the mean score for all students taking the course. ___________________ _ to ___________________ _
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xiazhe · **Reply #1 on:** Jun 24, 2018

Answer to Question 1

6.206; 6.794; If we repeatedly draw samples of size 100 from the population of teenagers, 95 of the values of sample means x will be such that the population mean amount of time teenagers spend on the internet () would be somewhere between 6.206 hours and 6.794, and 5 of the values of x will produce intervals that would not include .

Answer to Question 2

64.92; 83.48