Difference between two means: pooled t-test

Difference between two means: pooled t-test Quiz

Spec 7.3 · Edexcel A-Level Further Maths: Quiz

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  1. 1. Two samples of sizes 77 and 99 are used in a pooled tt-test. How many degrees of freedom are there?

    • A. 1414
    • B. 1515
    • C. 1616
    • D. 1313

  2. 2. Samples of sizes 55 and 88 have variances 2.02.0 and 3.03.0. What is the pooled variance?

    • A. 2.52.5
    • B. 2.732.73
    • C. 2.642.64
    • D. 2.362.36

  3. 3. A 95%95\% confidence interval for μX−μY\mu_X-\mu_Y is (−0.4, 2.2)(-0.4,\ 2.2). Which conclusion is correct?

    • A. μX>μY\mu_X>\mu_Y at the 5%5\% level
    • B. No evidence of a difference in means at the 5%5\% level (two-tailed)
    • C. μX<μY\mu_X<\mu_Y at the 5%5\% level
    • D. The means are proved equal

  4. 4. For a pooled test with 1111 degrees of freedom, two-tailed at 5%5\%, which critical value is used?

    • A. 1.7961.796
    • B. 2.2282.228
    • C. 1.8121.812
    • D. 2.2012.201

  5. 5. Which statement about the pooled tt-test is correct?

    • A. It is used when each value in one sample is paired with a value in the other
    • B. It needs the two sample sizes to be equal
    • C. It assumes equal population variances, which are unknown
    • D. It needs the sample variances to be equal

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