(a) A test preparation company wants evidence that their course improves students' scores on the ACT exam. From a random sample of 40 students who took the course, they do a paired t-test to compare the students' scores on the ACT exam before the course with their scores after the course (subtracting in the order (after - before)). The test has a test statistic of t = 2.06; what is the P-value of the test? Round to 3 decimal places. P=0.0231 (b) A researcher is interested in the effects of screentime on sleep. She wants to estimate the average number of hours of screentime that college students get between 9 pm and when they go to sleep. A random sample of 28 college students has an average amount of screentime after 9 pm of 1.2 hours with a standard deviation of 0.7 hours. Calculate a 95% confidence interval for the average amount of screentime that college students get between 9 pm and when they go to sleep. Round to 3 decimal places. CI = (0.941 (c) A company that manufactures X-ray machines wishes to estimate the proportion of their machines that malfunction and produce excess radiation. A random sample of 56 of the machines is taken and 11 of the machines malfunction. Find a 90% confidence interval for the true proportion of the company's machines that malfunction. Round to 3 decimal places. CI = (
(a) A test preparation company wants evidence that their course improves students' scores on the ACT exam. From a random sample of 40 students who took the course, they do a paired t-test to compare the students' scores on the ACT exam before the course with their scores after the course (subtracting in the order (after - before)). The test has a test statistic of t = 2.06; what is the P-value of the test? Round to 3 decimal places. P=0.0231 (b) A researcher is interested in the effects of screentime on sleep. She wants to estimate the average number of hours of screentime that college students get between 9 pm and when they go to sleep. A random sample of 28 college students has an average amount of screentime after 9 pm of 1.2 hours with a standard deviation of 0.7 hours. Calculate a 95% confidence interval for the average amount of screentime that college students get between 9 pm and when they go to sleep. Round to 3 decimal places. CI = (0.941 (c) A company that manufactures X-ray machines wishes to estimate the proportion of their machines that malfunction and produce excess radiation. A random sample of 56 of the machines is taken and 11 of the machines malfunction. Find a 90% confidence interval for the true proportion of the company's machines that malfunction. Round to 3 decimal places. CI = (
Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.3: Measures Of Spread
Problem 1GP
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Transcribed Image Text:(a) A test preparation company wants evidence that their course improves students' scores on the ACT exam. From a
random sample of 40 students who took the course, they do a paired t-test to compare the students' scores on the ACT
exam before the course with their scores after the course (subtracting in the order (after - before)). The test has a test
statistic of t = 2.06; what is the P-value of the test? Round to 3 decimal places.
P=0.0231
(b) A researcher is interested in the effects of screentime on sleep. She wants to estimate the average number of hours of
screentime that college students get between 9 pm and when they go to sleep. A random sample of 28 college students
has an average amount of screentime after 9 pm of 1.2 hours with a standard deviation of 0.7 hours. Calculate a 95%
confidence interval for the average amount of screentime that college students get between 9 pm and when they go to
sleep. Round to 3 decimal places.
CI = (0.941
(c) A company that manufactures X-ray machines wishes to estimate the proportion of their machines that malfunction
and produce excess radiation. A random sample of 56 of the machines is taken and 11 of the machines malfunction. Find
a 90% confidence interval for the true proportion of the company's machines that malfunction. Round to 3 decimal
places.
CI = (
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