The scores on a placement test given to college freshmen for the last five years are approximately normally distributed with a mean u = 74and a variance o = 8. Would you still consider o = 8 to be a valid value of the variance if a random sample of 20 students who take theplacement test this year obtained a sample variance of s = 20? Use 0.05 as a cutoff for a small probablity.2Yes,o2= 8 is valid because there is a large probability of obtaining a sample variance greater than 20Yes,o2= 8 is valid because there is a small probability of obtaining a sample variance greater than 20No,o2= 8 is not valid because there is a large probability of obtaining a sample variance greater than 20No,o2= 8 is not valid because there is a small probability of obtaining a sample variance greater than 20

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Answered: The scores on a placement test given to…

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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A sample of 9 days over the past six months showed that that Philip Sherman, DDS, treated the following numbers of patients: 22, 25, 20, 18, 15, 22, 24, 19, and 26. If the number of patients seen per day is normally distributed, would an analysis of these sample data reject the hypothesis that the variance in the number of patients seen per day is equal to 10? Use a = 0.10 level of significance. Use Table 3 from Appendix B. State the hypotheses. Ho: 0² = H₂: 0² 10 Calculate the variance and test statistic. (to 2 decimals) variance = test statistic = What is your conclusion? 10 Do not reject the null hypothesis ✓
what does MS stand for in analysis of variance?
An empirical researcher reports the following for a particular stock: “In ourdata sample we find that the variance of (de-trended) ex post stock prices is128 whereas the variance of (de-trended) actual stock prices is 110.” Whatmay this tell us? Are there any potential problems with what it may tell us?
Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 7.6 parts/million (ppm). A researcher believes that the current ozone level is not at a normal level. The mean of 1313 samples is 7.2 ppm with a variance of 0.49 Assume the population is normally distributed. A level of significance of 0.02 will be used. Make the decision to reject or fail to reject the null hypothesis.
IQs measured on a certain scale are normally distributed with a mean of 90 and a variance of 400. whats the probability that a random person will have an IQ between 120 and 130. the IQ of 51 people was taken, a sample mean of 90 and standard deviation of 64 was obtained. does this support that people tend to have IQs<100? use a 5% level of significance.
Records from previous years for a casualty insurance company show that its clients average a combined total of 1.9 auto accidents per day, with a variance of 0.31. The actuaries of the company claim that the current variance, oʻ, of the number of accidents per day is not equal to 0.31. A random sample of 17 recent days had a mean of 2 accidents per day with a variance of 0.62. If we assume that the number of accidents per day is approximately normally distributed, is there sufficient evidence to conclude, at the 0.05 level of significance, that the actuaries are correct? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified below. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the alternative hypothesis H,. p H, :0 H, :0 (b) Determine the type of test statistic to use. (Choose one) ▼ D=0 OSO O20 (c) Find the value of the test statistic. (Round…
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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.
A researcher wants to measure average cardiovascular health of university students and compare those scores to the average scores in the general population. Assuming that population variance is known, what statistical test is most appropriate for this study? independent-samples t-test single-sample t-test z-test for sample mean related-samples t-test

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