In a sample of 8 observations, the sum of squared deviations of items from the mean was 84.4. Inanother sample of 10 observations, the value was found to be 102.6. Test whether the difference issignificant at 5% level.You are given that at 5% level, critical value of F for V1 = 7 and v2 = 9 degrees of freedom is 3.29 andfor V1 = 8 and V2 = 10 degrees of freedom, its value is 3-07.

The significance of equality of population variance using the F test. Let us consider that the…

Answered: In a sample of 8 observations, the sum…

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 psychologist is studying smokers' self-images, which she measures using the self-image (SI) score from a personality inventory. She would like to examine the mean SI score u for the population of all smokers. Previously published studies have indicated that the mean SI score for the population of all smokers is 85 and that the standard deviation is 12, but the psychologist has good reason to believe that the value for the mean has decreased. She decides to perform a statistical test and chooses a random sample of 75 smokers' SI scores. She'll use the value 12 for the population standard deviation, and she'll test at the 0.05 level of significance. Based on this information, answer the questions below. Carry your intermediate computations to four or more decimal places, and round your responses as indicated. (If necessary, consult a list of formulas.) (a) What are the null hypothesis H, and the alternative hypothesis H, that the psychologist should use for the test? Ho: 0 H1: 0 O=0…
After the analyses, Rosalind found a significant difference in test scores between taking the test somewhere on campus and taking it in the classroom, t(41)=2.02, p=.049. However, Rebecca found no significant difference between those who took the test somewhere on campus and those who took it in the classroom, t(41)=1.68, p=.099. Considering that Rebecca had a larger mean difference between the two conditions than Rosalind, why are their results so different? I think this deals with type I and type II error giving false positive and false negative respectively, but I wanted to know if there could possibly be anything additional.
The relationship between birth weight and IQ were studied. 258 subjects with extremely low birth weights had Wechsler IQ scores at age 8 with a mean of 95.5 and a standard deviation of 16.0. For 220 individuals with normal birth weights, the mean at age 8 is 104.9 and the standard deviation is 13.8. Assume that the standard deviations are different, and determine if IQ score appears to be affected by birth weight. Use a = 0.1. 2a. b. Compute a 95% confidence interval on the difference between the means.
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A student takes a test in his math course and scores 45 points and a test in his psychology courseand scores 71 points. Scores on each test were normally distributed. On the math test the classhas a mean of 40 and a standard deviation of 15. On the psychology test the class has a mean of 75and a standard deviation of 10. On which test did the student do better?
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Do wearable devices that monitor diet and physical activity help people lose weight? Researchers had 237 subjects who were already involved in a program of diet and exercise use wearable technology for 24 months. They measured their weight (in kilograms) before using the technology and 24 months after using the technology. The 237 differences in weight (weight after 24 months minus weight before using the wearable technology) had ?⎯⎯⎯=−3.5�¯and ?=7.8.. Let ?� be the mean weight difference. What is the test statistic? Give your answer to three decimal places. ?= Identify the correct interpretation of the results based on your analysis.Which is the correct answer ? There is very convincing evidence that there is a decrease in average weight after wearing the device. There is a small amount of evidence that there is a decrease in average weight after wearing the device. There is very convincing evidence that there is an increase in average weight…
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Use z scores to compare the given values. The tallest living man at one time had a height of 238 cm. The shortest living man at that time had a height of 142.4 cm. Heights of men at that time had a mean of 175.45 cm and a standard deviation of 5.59 cm. Which of these two men had the height that was more extreme? ... Since the z score for the tallest man is z = 0 and the z score for the shortest man is z = the man had the height that was Im- more extreme. (Round to two decimal places.) shortest tallest
A statistics teacher taught a large introductory statistics class, with 500 students having enrolled over many years. The mean score over all those students on the first midterm was u = 88 with standard deviation o = 10. One year, the teacher taught a %3D much smaller class of only 25 students. The teacher wanted to know if teaching a smaller class was more effective and students performed better. We can consider the small class as an SRS of the students who took the large class over the years. The average midterm score was = 78. The hypothesis should be: a. Ho: H = 78 vs. Ha: H = 88. %3D O b. Ho: µ = 88 vs. Ha: µ 78 %3D Ο d. Ho: μ-88 νs. Ha: μ >88. %3D

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