A company is doing a hypothesis test on the variation ofquality from two suppliers. Both distributions are normal,and the populations are independent. use a = 0.012 = 0 2?2HA : σ12> 0 2The standard deviation of the first sample is 3.43644.8785 is the standard deviation of the second sample.The test statistic isFail to reject the null hypothesisReject the null hypothesis

Given that A company is doing hypothesis test of variance. Both distributions are normal and…

Answered: A company is doing a hypothesis test on…

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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Scores on a certain test are normally distributed with a variance of 90. A researcher wishes to estimate the mean score achieved by all adults on the test. Find the sample size needed to assure a 95 percent confidence interval with a width of 4.
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A psychologist wants to test whether there is any difference in puzzle-solving abilities between boys and girls. Independent samples of eleven boys and seven girls were chosen at random. The boys took a mean of 37 minutes to solve a certain puzzle, with a standard deviation of 4.8 minutes. The girls took a mean of 35 minutes to solve the same puzzle, with a standard deviation of 4.5 minutes. Assume that the two populations of completion times are normally distributed, and that the population variances are equal. Can we conclude, at the 0.10 level of significance, that the mean puzzle-solving times for boys, μ1 is greater than the mean puzzle-solving times for girls, μ2? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. a. State the null hypothesis H0 and the alternative hypothesis H1. b. Find the value of the test statistic. (Round to three or more decimal…
Suppose that we are interested in comparing the academic success of college students who belong to fraternal organizations and the academic success of those who do not belong to fraternal organizations. Random samples of size 40 are taken from each population where the variances and standard deviations are known. Sample Size Mean GPA Variance (2) 2.03 2.21 Fraternity member (f): 40 Nonmembers (n): 40 .46 .35 Construct a 96% confidence interval estimate for the difference between the mean GPAS (uf- un). Interpret this interval estimate. What can you conclude about the mean GPAs of the two groups?
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A study has been made to compare the nicotine contents of two brands of cigarettes. Ten cigarettes of Brand A had an average nicotine content of 4.3 milligrams with a standard deviation of 0.6 milligram. Eight cigarettes of Brand B had an average nicotine content of 3 milligrams with a standard deviation of 0.4 milligram. Assume that the two sets of data are independent random samples from normal populations with equal variances. Answer the following, and round off your answer to three decimal places. (a) Find a pooled estimate of the population standard deviation. (b) Construct a 95% confidence interval for the difference between the mean nicotine contents of the two brands of cigarettes. (☐☐)
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The means of the number of revolutions per minute of two competing engines are to be compared. Thirty engines are randomly assigned to be tested. Both populations have normal distributions. Table 10.4 shows the result. Do the data indicate that Engine 2 has higher RPM than Engine 1? Test at a 5% level of significance. Engine Sample Mean Number of RPM Population Standard Deviation 1 1,500 50 2 1,600 60
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A researcher decides to measure anxiety in group of bullies and a group of bystanders using a 23-item, 3 point anxiety scale. Assume scores on the anxiety scales are normally distributed and the variance among the group of bullies and bystanders are the same. A group of 30 bullies scores an average of 21.5 with a sample standard deviation of 10 on the anxiety scale. A group of 27 bystanders scored an average of 25.8 with a sample standard deviation of 8 on the anxiety scale. You do not have any presupposed assumptions whether bullies or bystanders will be more anxious so you formulate the null and alternative hypothesis based on that.

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