To evaluate the effect of a treatment, asample of n= 8 is obtained from apopulation with a mean of µ = 40, and the%|treatment is administered to the individualsin the sample. After treatment, the samplemean is found to be M= 35.a. If the sample variance is s = 32, are the%|data sufficient to conclude that thetreatment has a significant effect using atwo-tailed test with a = .05?b. If the sample variance is s² = 72, are thedata sufficient to conclude that thetreatment has a significant effect using atwo-tailed test with a = .05?c. Comparing your answer for parts a and b,how does the variability of the scores in thesample influence the outcome of ahypothesis test?

Answered: Image /qna-images/answer/e17d2013-3434-4b59-ba07-556e4aba61d2.jpg

Answered: To evaluate the effect of a treatment,…

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 therapist would like to evaluate an intervention for treating depression. A sample of n = 20 depressed clients is obtained, and each person’s level of depression is measured using a standardized questionnaire before they begin the therapy program. Two weeks after therapy, each client’s level of depression is measured again. The average level of depression dropped by 4.0 points following therapy. The difference scores had a variance of 64. Identify and Cclculate the appropriate test statistic.Make sure to report the degrees of freedom for the statistical test (if appropriate). You must show your work to receive full credit. State your conclusions (use a two-tailed test with a = .05 for all tests). Compute an effect size.
A nutrition store in the mall is selling "Memory Booster" which is a concoction of herbs and minerals that is intended to improve memory performance. To test the effectiveness of the herbal mix, a researcher obtains a sample of n = 16 people and has each person take the suggested dosage each day for 4 weeks. At the end of the four-week period, each individual takes a standardized memory test. The scores from the sample produced a mean of M = 26 with a sample variance of s2 = 64. In the general population, the standardized test is known to have a mean of μ = 20. 1. Do the sample data support the conclusion that the Memory Booster has a significant "booster" effect? Test with α = .05. Hint: think about 1- or 2-tail test to use. 2. Compute Cohen's d and r2 to measure the treatment effect size.
Suppose we wish to compare the variation in diameters of parts produced by company A with the variation in diameters of parts produced by company B. The sample variance of company A, based on n = 19 diameters, was, s1 2 = 0.0012, while the sample variance of the 20 diameter measurements from the company B has sample variance, s2 2 = 0.0017. Do the data provide sufficient information to indicate a larger variance in diameters for company B?. Test with X = 0.1.
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if a researcher undertook an experiment to evaluate the efficacy of a memory enhancement technique among a cohort of 15 college students. The memory recall abilities of each student were assessed both before and after they underwent training in the memory technique. The observed average increase in memory recall scores following the training was 5 points. The sample variance of the differences within the entire sample was denoted as 8. Does this research question aim to ascertain whether there is a statistically significant elevation in memory recall scores after the implementation of the memory improvement training? To address this question, a one-tailed test with a significance level of (alpha = 0.01) is employed.
Highway engineers in Ohio are painting white stripes on a highway. The stripes are supposed to be approximately 10 feet long. However, because of the machine, the operator, and the motion of the vehicle carrying the equipment, considerable variation occurs among the stripe lengths. Engineers claim that the variance of stripes should be less than 16 inches squared. At α = .05, use the sample lengths given here from 12 measured stripes (in feet and inches) to test the variance claim. Assume stripe length is normally distributed. (in feet) (in inches) 9.85 118.2 9.7 116.4 9.9 118.8 9.5 114 9.15 109.8 10.1 121.2 10 120 9.8 117.6 9.9 118.8 10.3 123.6 10.1 121.2 10.2 122.4 The appropriate test for this question is: a Z-test for the true variance of stripe length. a t-test for the true mean of stripe length. a Chi-square test…
An analysis of variances produces dftotal = 35 and dfwithin = 32. For this analysis, what is dfbetween?
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An analysis of variances produces dftotal = 16 and dfwithin = 14. For this analysis, how many treatment conditions are being compared?
Sony would like to test the hypothesis that the average age of a PlayStation user is different from the average age of an Xbox user. A random sample of 32 PlayStation users had an average age of 33.7 years while a random sample of 36 Xbox users had an average age of 35.6 years. Assume that the population standard deviation for the age of PlayStation and Xbox users is 3.7 and 3.5 years, respectively. Also assume population variances are equal. Sony would like to set alpha= 0.05. The 95% confidence interval for the difference in population means is

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