Question

question 6
1 pts
ch 20 robustness means that the confidence level or p - value changes a lot when the conditions for use of the procedures are violated.
true
false
question 7
1 pts
ch 20 a student wanted to assess the average time spent studying for his most recent exam taken in class. he asked the first 45 students who came to class how much time they spent and recorded the values. he then used this information to calculate a 95% confidence interval for the mean time spent by all students. was this an appropriate use of the t procedure for a confidence interval? (hint: check conditions.)
yes, because the 45 students is a big enough sample to invoke the clt
yes, because we can assume that the time spent studying was normally distributed
no, because there was no randomization in choosing the sample
no, because time spent studying is not a quantitative variable

Explanation:

For Question 6: Robustness means that the confidence level or P - value does not change much when the conditions for use of the procedures are violated. So the statement in Question 6 is incorrect.
For Question 7: To use the t - procedure for a confidence interval, one of the important conditions is random sampling. The student only asked the first 45 students who came to class (not a random sample). The Central Limit Theorem (CLT) requires random sampling as a basis. Also, time spent studying is a quantitative variable. And we cannot assume normality just because of the sampling method used (non - random).

Answer:

Question 6: False
Question 7: no, because there was no randomization in choosing the sample