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# A test for differences in variance.

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Randomly selected statistics students were given five seconds to estimate the value of a product of numbers with a summary of the results of both groups given below. Does the order of the numbers appear to have an effect on the variances? Use a 0.05 significance level to test the difference between variances of the two samples. Use the traditional method to perform the test.

Order 1: Estimates from 40 Students Given: 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8
n = 28 x-bar = 28,344.9 s = 5,667.9

Order 2: Estimates from 42 Students Given: 8 X 7 X 6 X 5 X 4 X 3 X 2 X 1
n = 25 x-bar = 36,001.0 s = 7,679.4

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##### Solution Summary

The following outlines the process for using an F-stat to determine if the difference in variances from two randomly selected groups are statistically significant.

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Randomly selected statistics students were given five seconds to estimate the value of a product of numbers with a summary of the results of both groups given below. Does the order of the numbers appear to have an effect on the variances? Use a 0.05 ...

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###### Education
• BSc , Wuhan Univ. China
• MA, Shandong Univ.
###### Recent Feedback
• "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
• "excellent work"
• "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
• "Thank you"
• "Thank you very much for your valuable time and assistance!"

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