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Concept explainers
For Exercises 7 through 23, perform each of the following steps.
a. State the hypotheses and identify the claim.
b. Find the critical value(s).
c. Find the test value.
d. Make the decision.
e. Summarize the results.
Use the traditional method of hypothesis testing unless otherwise specified.
11. Television Viewing by Teens Teens are reported to watch the fewest total hours of television per week of all the demographic groups. The average television viewing for teens on Sunday from 1:00 to 7:00 P.M. is 58 minutes. A random sample of local teens disclosed the following times for Sunday afternoon television viewing. At α = 0.01, can it be concluded that the average is greater than the national viewing time? (Note: Change all times to minutes.)
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Chapter 8 Solutions
Elementary Statistics: A Step By Step Approach
- Suppose you know that Bob's test score is above the mean, but he doesn't remember by how much. At least how many students must score lower than Bob?arrow_forwardIf a baby's weight is at the median, what's her percentile?arrow_forwardAt the same restaurant as in Question 19 with the same normal distribution, what's the chance of it taking no more than 15 minutes to get service?arrow_forward
- Clint, obviously not in college, sleeps an average of 8 hours per night with a standard deviation of 15 minutes. What's the chance of him sleeping between 7.5 and 8.5 hours on any given night? 0-(7-0) 200 91109s and doiw $20 (8-0) mol 8520 slang $199 galbrog seam side pide & D (newid se od poyesvig as PELEO PER AFTE editiw noudab temand van Czarrow_forwardTimes to complete a statistics exam have a normal distribution with a mean of 40 minutes and standard deviation of 6 minutes. Deshawn's time comes in at the 90th percentile. What percentage of the students are still working on their exams when Deshawn leaves?arrow_forwardSuppose that the weights of cereal boxes have a normal distribution with a mean of 20 ounces and standard deviation of half an ounce. A box that has a standard score of o weighs how much? syed by ilog ni 21arrow_forward
- Bob scores 80 on both his math exam (which has a mean of 70 and standard deviation of 10) and his English exam (which has a mean of 85 and standard deviation of 5). Find and interpret Bob's Z-scores on both exams to let him know which exam (if either) he did bet- ter on. Don't, however, let his parents know; let them think he's just as good at both subjects. algas 70) sering digarrow_forwardSue's math class exam has a mean of 70 with a standard deviation of 5. Her standard score is-2. What's her original exam score?arrow_forwardClint sleeps an average of 8 hours per night with a standard deviation of 15 minutes. What's the chance he will sleep less than 7.5 hours tonight? nut bow visarrow_forward
- Suppose that your score on an exam is directly at the mean. What's your standard score?arrow_forwardOne state's annual rainfall has a normal dis- tribution with a mean of 100 inches and standard deviation of 25 inches. Suppose that corn grows best when the annual rainfall is between 100 and 150 inches. What's the chance of achieving this amount of rainfall? wved now of sociarrow_forward13 Suppose that your exam score has a standard score of 0.90. Does this mean that 90 percent of the other exam scores are lower than yours?arrow_forward
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