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.
In one study (survey), participants gave their answers on a scale of 1-5 (1=strongly disagree with 5=strongly agree). The average of the responses of 120 men participating in the study was found to be 4.06 and the standard deviation was 0.6, and the average of the responses of 162 women was found to be 3.46 and the standard deviation was 0.4. which of the following is the test statistic calculated when conducting a test of whether the actual average of men's responses at the meaning level of 0.01 is higher than that of women?Answer options group A)4,82 B)2,33 C)7,10 D)9.50
You are comparing data from two similar experiments that have a mean of 53. Experiment A has a standard deviation of 3.4 and experiment B has a standard deviation of 1.5. What does this tell you about the data in the experiments?
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?
A psychologist wants to estimate the amount of math anxiety that the population of high school students experience prior to taking their first algebra course. On the first day of class he asks a sample of 36 students to answer the question, “How anxious do you feel when you know you have to do math problems?” They each responded using a 100-point scale with 1 = not at all anxious and 100 = extremely anxious. The mean reported anxiety score for this sample was 58 with a standard deviation of 30 Compute the upper and lower boundaries for this 95% confidence interval. LB = 66.45, UB - 49.55 LB = 28, UB = 88 LB = -5.00, UB = 5.00 LB = 47.86, UB = 68.15 LB = -10.15, UB = 10.15
A researcher wanted to know whether losing one night sleep can affect problem solving. A sample of n = 25 college students was given a problem-solving task at noon on one day and again at noon on the following day. The students were not permitted any sleep between the two tests. For each student, the difference between the first and the second score was recorded: MD = 5 and standard deviation of the difference score was s = 10. Do the data indicate a significant change in problem solving ability? Use a two-tailed test with α = .01. a. The alternative hypothesis in words is b. The null hypothesis in symbols is c. The critical t-values are d. The t-statistic is e. Your decision is
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…
Mason earned a score of 226 on Exam A that had a mean of 250 and a standard deviation of 40. He is about to take Exam B that has a mean of 550 and a standard deviation of 25. How well must Mason score on Exam B in order to do equivalently well as he did on Exam A? Assume that scores on each exam are normally distributed.
A sample of size 50 will be drawn from a population with mean 76 and standard deviation 14. Find the 69th percentile of x.
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

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