aianjie

 

 

The correct answer is B

This is a two-tailed test of the difference of means with equal population variance. The test statistic is:

 

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[2008] Topic 6: Statistical Inference: Estimation and Hypothesis Testing 相关习题

2009-6-26 09:14

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[2008] Topic 6: Statistical Inference: Estimation and Hypothesis Testing 相关习题

2009-6-26 09:14

 

 

The degrees of freedom is n₁ + n₂ – 2 = 25 + 36 – 2 = 59.

t-critical = 2.000 with degrees of freedom = 25 + 36 – 2 = 59. Therefore, we reject the null hypothesis (|–3.42| > 2.00). Please note that t-tables seldom report the exact values for higher df like 59. Since 60 df is the closest value that is reported, we use the t-value for 60 df = 2.000.

aianjie

 

Using a 5 percent level of significance for a test of the null of H0: σ1 = σ2 versus the alternative of Ha: σ1 ? σ2, the null hypothesis:

A) cannot be rejected.

B) should be rejected.

C) should neither be rejected nor fail to be rejected.

D) cannot be tested using the sample information provided. 

aianjie

 

The correct answer is A

The two-sided F-test is appropriate to test the equality of population variances. The decision rule is to reject H₀ if the computed test statistic, F, exceeds the critical F-value at α/2. For the information provided, F = 

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2009-6-26 09:24

   = 36/25 = 1.44. At a 0.025 level of significance with d₁ = 35 and d₂ = 24, F-critical = 1.915. Since F < F-critical (1.44 < 1.915), we fail to reject the null hypothesis.

aianjie

 

4、The test statistic for an F-test of the equality of two sample variances is the:

A) product of the two sample variances.

B) ratio of the two sample standard deviations.

C) product of the two sample standard deviations.

D) ratio of the two sample variances.

aianjie

 

The correct answer is D

The test statistic for an F-test of the equality of two sample variances is the ratio of the two sample variances.

 

 

 

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2009-6-26 09:25

aianjie

 

5、What is the computed value of the test statistic that follows an F-distribution when sample variances are equal and the level of significance is 0.10?

A) 0.05.

B) 0.90.

C) 1.00.

D) 0.10.

aianjie

 

The correct answer is C

The calculated value of the F-distributed test statistic, F, is s12 / s22. With equal variances, F = 1.