A simple random sample of 56 students who picked up all tests they completed was selected, and the mean score on the final exam for this sample of students was 83 with a standard deviation of 10.4. An independent simple random sample of 51 students who had one or more tests that were not picked up was
A simple random sample of 56 students who picked up all tests they completed was selected, and the mean score on the final exam for this sample of students was 83 with a standard deviation of 10.4. An independent simple random sample of 51 students who had one or more tests that were not picked up was selected, and the mean score on the final exam for this sample of students was 67 with a standard deviation of 24.2. Both distributions are skewed heavily to the left [note: this is the same information provided in the previous scenario]. If appropriate, use this information to calculate and interpret a 99% confidence interval for the difference in the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up.
Are the assumptions met?
No, because the distributions are heavily skewed to the left
Yes, because any sample size will work and there are 2 simple random samples
Yes, because both samples are larger than 40 and there are 2 simple random samples
Yes, because both samples are larger than 15 and there are 2 simple random samples
Yes, because both samples are larger than 30 and there are 2 simple random samples
What are the confidence interval values using 99% confidence?
None of these
(13.506, 20.494)
(6.6985, 25.302)
(6.2876, 25.712)
(11.615, 26.385)
(6.5658, 25.434)
Which of the following is a correct interpretation of the 99% confidence interval computed in the previous question?
None of these
We have 99% confidence that the difference in the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up is between 6.2876 and 25.712.
We have 95% confidence that the difference in the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up is between 6.5658 and 25.434.
We have 99% confidence that the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up is between 6.2876 and 25.712.
We have 95% confidence that the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up is between 6.5658 and 25.434.
We have 90% confidence that the difference in the mean score on the final exam for all students who picked up all their tests and the mean score on the final exam for all students who had one or more tests that were not picked up is between 6.6985 and 25.302.
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