ECN 221 Midterm 3 Exam
1. What type of error occurs if you fail to reject H0 when, in fact, it is not true?: Type
II
2. For a lower tail test, the p-value is the probability of obtaining a value for the
test statistic as: smaller as or smaller than thats provided with the sample
3. The p-value is a probability that measures the support (or lack of support)
for: the null hypothesis
4. The calorie content is listed as 241 calories for a prepared meal. Tawnya
tests a sample of 30 meals finding a mean of 249.6 calories with a standard
deviation of 7.8 calories. Test to determine if the company preparing the meals
is packaging meals with a different calorie content than stated on the label at
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, a 1% (0.01) level of significance using the critical value approach.: The hypotheses are
H0: 5= 241 calories and Ha: 5`241 calories. The test statistic is t = 6.039. The critical values are ±2.756. The conclusion is
to reject H0. We conclude that the mean calorie content in meals is significantly different than 241 calories.
5. The proportion of Nadya's sales on Etsy that were returned after purchase
in the second quarter of the year was 0.073. To determine if the proportion of
purchases returned in the third quarter has changed, Nadya selected a random
sample of 200 sales finding 19 of them were returned. Conduct the appropriate
test of hypothesis at 5=ü0.1 using the critical value method.: The hypotheses are H0: p =
0.073 and Ha: p `0.073. The test statistic is z = 1.20. The critical values are ±1.645. The conclusion is to not reject H0.
We cannot conclude that the proportion of third quarter returns is significantly different from the 7.3% in the second
quarter.
6. A Type II error is committed when: a true alternative hypothesis is mistakenly rejected
7. The error of rejecting a true null hypothesis is: a Type 1 error
2/5
1. What type of error occurs if you fail to reject H0 when, in fact, it is not true?: Type
II
2. For a lower tail test, the p-value is the probability of obtaining a value for the
test statistic as: smaller as or smaller than thats provided with the sample
3. The p-value is a probability that measures the support (or lack of support)
for: the null hypothesis
4. The calorie content is listed as 241 calories for a prepared meal. Tawnya
tests a sample of 30 meals finding a mean of 249.6 calories with a standard
deviation of 7.8 calories. Test to determine if the company preparing the meals
is packaging meals with a different calorie content than stated on the label at
1/5
, a 1% (0.01) level of significance using the critical value approach.: The hypotheses are
H0: 5= 241 calories and Ha: 5`241 calories. The test statistic is t = 6.039. The critical values are ±2.756. The conclusion is
to reject H0. We conclude that the mean calorie content in meals is significantly different than 241 calories.
5. The proportion of Nadya's sales on Etsy that were returned after purchase
in the second quarter of the year was 0.073. To determine if the proportion of
purchases returned in the third quarter has changed, Nadya selected a random
sample of 200 sales finding 19 of them were returned. Conduct the appropriate
test of hypothesis at 5=ü0.1 using the critical value method.: The hypotheses are H0: p =
0.073 and Ha: p `0.073. The test statistic is z = 1.20. The critical values are ±1.645. The conclusion is to not reject H0.
We cannot conclude that the proportion of third quarter returns is significantly different from the 7.3% in the second
quarter.
6. A Type II error is committed when: a true alternative hypothesis is mistakenly rejected
7. The error of rejecting a true null hypothesis is: a Type 1 error
2/5
