Testing a Claim about a Mean Difference — Quiz Answers

The principal of a large high school wants to improve student test scores, so he asks one of his science teachers to try a new method of teaching. Thirty-one students take a pretest on the first day of science class. After 6 weeks using the new instruction, the same students take a posttest. The mean difference open paren posttest minus pretest close paren in scores is 4 point 8 points with a standard deviation of 9 point 7 points. Assuming the conditions for inference are met, what is the cap p -value for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 ; ratio of cap h sub A to mu sub diff is greater than 0 ? Use the t -table.

A music professor is interested in the effects of listening to music while memorizing a list of words. She asks 14 volunteers to memorize two different lists of words: one list while listening to music in the background and the other list with no music in the background. The order of the treatments is determined by a coin toss. The mean difference open paren music minus no music close paren in the number of words memorized is 4 point 1 words with a standard deviation of 3 point 8 words. Assuming that the conditions for inference are met, what is the cap p -value for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 ; ratio of cap h sub A to mu sub diff is greater than 0 ? Use the t -table.

Chuck wants to know which brand of tire, cap A or cap b , lasts longer on cars. He chooses 32 cars and puts brand cap A on one side of the car and brand cap b on the other side. The side that receives brand cap A is determined by a coin toss. After three months, Chuck measures the amount of tread on all tires to determine if, on average, there is a difference open paren brand A minus brand B close paren in tread wear. Are the conditions for inference met?

An equestrian enthusiast is interested in the racing times of horses. She believes an older horse will have a faster race time than a younger horse. She selects a random sample of 17 sibling pairs of adult horses and records their times for running on the same track. The mean difference open paren older minus younger close paren in the times to run the track is negative 15 point 7 seconds with a standard deviation of 8 point 3 seconds. What are the hypotheses the equestrian should use?

The principal of a large high school wants to improve student test scores, so he asks one of his science teachers to try a new method of teaching. Thirty-one students take a pretest on the first day of science class. After 6 weeks using the new instruction, the same students take a posttest. The mean difference open paren posttest minus pretest close paren in scores is 4 point 8 points with a standard deviation of 9 point 7 points. Assuming the conditions for inference are met, what is the test statistic for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 ; ratio of cap h sub A to mu sub diff is greater than 0 ?

A music professor is interested in the effects of listening to music while memorizing a list of words. She asks 14 volunteers to memorize two different lists of words: one list while listening to music in the background and the other list with no music in the background. The order of the treatments is determined by a coin toss. The mean difference open paren music minus no music close paren in the number of words memorized is 4 point 1 words with a standard deviation of 3 point 8 words. Assuming that the conditions for inference are met, what is the test statistic for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 ; ratio of cap h sub A to mu sub diff is greater than 0 ?

An equestrian enthusiast is interested in the racing times of horses. She believes an older horse will have a faster race time than a younger horse. She selects a random sample of 17 sibling pairs of adult horses and records their times for running on the same track. The mean difference open paren older minus younger close paren in the times to run the track is negative 15 point 7 seconds with a standard deviation of 8 point 3 seconds. Are the conditions for inference met?

Chuck wants to know which brand of tire, cap A or cap b , lasts longer on cars. He chooses 32 cars and puts brand cap A on one side of the car and brand cap b on the other side. The side that receives brand cap A is determined by a coin toss. After three months, Chuck measures the amount of tread on all tires to determine if, on average, there is a difference open paren brand A minus brand B close paren in tread wear. What are the hypotheses Chuck should use?

A nurse at a local hospital wonders if the firstborn twin is taller than the second-born. He randomly selects the medical records of 33 sets of twins and finds the differences open paren firstborn minus second-born close paren in the twins’ heights, in centimeters. The mean of the differences is 1 point 1 centimeters with a standard deviation of 2 point 3 centimeters. Assuming the conditions for inference are met, what is the cap p -value for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 ; ratio of cap h sub A to mu sub diff is greater than 0 ? Refer to the t -table.

A nurse at a local hospital wonders if the firstborn twin is taller than the second-born. He randomly selects the medical records of 33 sets of twins and finds the differences open paren firstborn minus second-born close paren in the twins’ heights, in centimeters. The mean of the differences is 1 point 1 centimeters with a standard deviation of 2 point 3 centimeters. Assuming that the conditions for inference are met, what is the test statistic for testing the hypotheses ratio of cap h sub 0 to mu sub diff is equal to 0 , ratio of cap h sub A to mu sub diff is greater than 0 ?