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Part CCSIR NET June 2024one-degree-of-freedom-goes-to-the-total

One degree of freedom goes to the total

Consider a six faced die whose i-th face is marked with i dots, i = 1, 2, …, 6. In a single random throw of the die, let pip_{i} denote the probability that the obtained upper face has i dots, i = 1, 2, …, 6. The die is rolled 240 times independently and the following result is obtained — face observed 1, 2, 3, 4, 5, 6 with frequencies 40, 55, 40, 25, 35, 45 respectively. Suppose we want to test H0:pi=1/6H_{0} : p_{i} = 1/6 for i = 1, 2, …, 6; against H1:pi≠1/6H_{1} : p_{i} \ne 1/6 for at least one i. It is given that χ52;0.05=11.07,χ62;0.05=12.59,χ52;0.01=15.09,χ62;0.01=16.81\chi^{2}_{5};_{0}._{05} = 11.07, \chi^{2}_{6};_{0}._{05} = 12.59, \chi^{2}_{5};_{0}._{01} = 15.09, \chi^{2}_{6};_{0}._{01} = 16.81. Based on the asymptotic goodness of fit χ2\chi^{2} test for testing H0H_{0} against H1H_{1}, which of the following statements are true?

  1. A.H0H_{0} is rejected at 5% level of significance✓ Correct
  2. B.H0H_{0} is rejected at 1% level of significance
  3. C.H0H_{0} is not rejected at 5% level of significance
  4. D.Observed value of the test statistic is 12.5✓ Correct

You have the answer. Trap Analysis is why the other three were written.

Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward, and why this one tests what the inference means.

See pricing

50 are analysed free — try those first.

The trap it tests

What the inference means

p-values, size, power and error types say specific things. This was not one of them.

Drill statements like this

Related counterexample: Any interval of the form [X̄ − (S/√n)t, ∞) with a 90% quantile t is a 90% confidence interval

More on this topic

The chapter behind this: Standard tests and confidence intervals — free to read

From Hypothesis Testing › Likelihood ratio and standard tests

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