Confidence level and interval width. Refer to given Exercise. Would a 90% confidence interval be wider or narrower than the one that you found in that exercise? Verify your answer by computing the interval.
Exercise
Are seniors prepared for class? The National Survey of Student Engagement found that 24% of seniors report that they often or very often went to class without completing readings or assignments. Assume that the sample size of seniors is 276,000.
(a) Find the margin of error for 99% confidence.
(b) Here are some items from the report that summarizes the survey. More than 537,000 students from 751 institutions in the United States and Canada participated. The average response rate was 33% and ranged from 15% to 87%. Institutions pay a participation fee of between $1800 and $7800 based on the size of their undergraduate enrollment. Discuss these as sources of error in this study. How do you think these errors would compare with the error that you calculated in part (a)?