A maintenance supervisor is comparing the standard version of an instruetional booklet with onethat has been claimed to be superior. An experiment is conducted in which 26 technicians aredivided into two groups, provided with one of the booklets, then given a test a week later. For the13 using the standard version, the average exam score was 72.0, with a standard deviation of 9.3.For the other 13 using the new version, the average score was 80.2, with the standard deviation of10.1. Assume normal populations with equal standard deviations, and using the 5% level ofsignificance, does the standard version booklet appear to be better than the new version?

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Answered: A maintenance supervisor is comparing…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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The calculation of the coefficient of determination r² depends on the number of independent variables. An adjusted value of r² based on the number of degrees of freedom is calculated using the formula shown below, where n is the number of data pairs and k is the number of independent variables. 2 adj =1- (1-2) (n-1) n-k-1 Data were found on eight pre-owned sedans of a certain make. Suppose a multiple regression on these data has 6 independent variables. The coefficient of determination is found to be 0.901 based on a sample of 18 paired 2 adj, observations. After calculating r determine the percentage of the variation in y that can be explained by the relationships between variables according to r2d. Compare this result with the one obtained using r². adj
A study was conducted to investigate the effect of a new drug on blood pressure. A sample of 25 patients was randomly selected and their blood pressure was measured both before and after taking the drug. The sample mean blood pressure before taking the drug was 120 mmHg and the sample mean blood pressure after taking the drug was 118 mmHg. The sample standard deviation for the blood pressure before taking the drug was 4 mmHg and the sample standard deviation for the blood pressure after taking the drug was 5 mmHg. Test the hypothesis that the average blood pressure after taking the drug is lower than the average blood pressure before taking the drug using a 0.01 level of significance.
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