In: Statistics and Probability
Question
Manufacturers are testing a die to make sure that it is fair (has a uniform distribution). They roll the die 84 times and record the outcomes in the table below.
Outcome | 1 | 2 | 3 | 4 | 5 | 6 |
---|---|---|---|---|---|---|
Expected | 14 | 14 | 14 | 14 | 14 | 14 |
Observed | 17 | 12 | 15 | 5 | 16 | 19 |
They perform a chi-square Goodness-of-Fit Test. The first few steps are summarized below.
Use the following portion of the χ2-table for the critical value.
df | χ20.10 | χ20.05 | χ20.025 | χ20.01 | χ20.005 |
---|---|---|---|---|---|
... | … | … | … | … | … |
4 | 7.779 | 9.488 | 11.143 | 13.277 | 14.860 |
5 | 9.236 | 11.070 | 12.833 | 15.086 | 16.750 |
6 | 10.645 | 12.592 | 14.449 | 16.812 | 18.548 |
7 | 12.017 | 14.067 | 16.013 | 18.475 | 20.278 |
8 | 13.362 | 15.507 | 17.535 | 20.090 | 21.955 |
Which is the correct conclusion of our goodness-of-fit test, at the
1% significance level?
Select the correct answer below:
Degrees of freedom =5.
Critical value: χ20.01=16.750.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should reject H0 because the test statistic falls in the rejection region (less than χ20.01).
Degrees of freedom =5.
Critical value: χ20.01=15.086.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should reject H0 because the test statistic falls in the rejection region (less than χ20.01).
Degrees of freedom =6.
Critical value: χ20.01=18.548.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should reject H0 because the test statistic falls in the rejection region (less than χ20.01).
Degrees of freedom =5.
Critical value: χ20.01=15.086.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should not reject H0 because the test statistic does not fall in the rejection region (greater than χ20.01).
Degrees of freedom =6.
Critical value: χ20.01=16.812.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should not reject H0 because the test statistic does not fall in the rejection region (greater than χ20.01).
Degrees of freedom =5.
Critical value: χ20.01=16.750.
Conclusion: The test statistic is less than the critical value χ20<χ20.01. So, we should not reject H0 because the test statistic does not fall in the rejection region (greater than χ20.01).