# How many degrees of freedom would the t statistic

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MS Model MS Error 2 2 T M s s 2 2 1 ln 2 M E s s SSM SSE
have for this hypothesis test?
6.12 How many degrees of freedom would the t-statistic
Practice Quiz 3 11 6.13 What is the critical value for this t-test?
6.15 Do you get the same results from the t-test and the F-test?
6.16 Why?
Practice Quiz 3 12 Problem 7 Cross tabulated count data A recent poll surveyed a simple random sample of 100 voters in Washington. Respondents were classified by age group and voting behavior. Use the following results to test the hypothesis that age is independent of voting behavior. OBSERVED Voted Did not vote Total 18 to 28 25 75 29 to 45 50 50 >45 75 25 Total 150 150 7.1 What is the general formula for the expected value of the cell counts under the null hypothesis that voting status is independent of age? ?(? ?? ) = ? +? ? ?+ ? ++ Work out the expected values in this table under the null hypothesis that age is independent of voting preference. Show both the formula with plug in values, and solve for the answer. (7.2-7.7) EXPECTED Voted Did not vote Total 18 to 28 7.2 50 7.3 50 100 29 to 45 7.4 50 7.5 50 100 >45 7.6 50 7.7 50 100 Total 150 150 7.8 What is the general formula for the contribution of each cell to the Chi-squared statistic? ? ?? 2 = (? ?? − ? ?? ) 2 ? ?? 100 100 100 300 300
Practice Quiz 3 13 Work out the squared standardized residuals ( z ij 2 ) in this table (7.9-7.14) z ij 2 Voted Did not vote 18 to 28 7.9 12.5 7.10 12.5 29 to 45 7.11 0 7.12 0 >45 7.13 12.5 7.14 12.5 7.15 What is the value of the Chi-square statistic for
7.16 How many degrees of freedom does the Chi- square statistic for this test have? Show the
formula with plug in values and the result 7.17 What is the α=0.05 critical value of the Chi - 𝜒 𝜒
8. Basic questions about statistical inference 8.1 The central limit theorem in statistics is used to make inferences about a. The distribution of a discrete random variable b. The sampling distribution of a sample mean c. The variance of a sample of size n d. The exponential approximation for a Normal distribution e. None of the above
8.2 P-values in hypothesis tests for a sample mean of the random variable X are based on
Practice Quiz 3 14
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