Chapter 8 - Means (Summary Stats) Input Output Sample Mean (x-bar) These outputs are ungraded but should be used in the calculation of the graded values below. Standard Deviation ( or s) Sample Size (n) 1 pt Standard Error We must treat data differently based on if we know the population standard deviation or not. Be sure you chose the correct method for each of the questions below dealing with confidence intervals for means. Just as before, use the template file to compute the values needed using Excel. For each question, we will then draw a conclusion. Remember there should be 1 to 2 parts to the conclusion, depending on how the question is worded. All intervals should first tell what the interval means IN CONTEXT. Go back to the question to interpret what the two endpoints are telling us. If your question also references a hypothesized value, you should then include the second part of the conclusion. Tell whether the interval values support the hypothesized value and what that means. Question 3 Question 3 7 Points Part I: Screenshot Professor Brehm wants to estimate how many hours per week her students study. A simple random sample of 84 students had a mean of 12 hours of study time per week. Construct and interpret a 90% confidence interval for the mean number of hours a student studies per week. Assume that the population standard deviation is known to be 2.1 hours per week. Part II: Conclusion Interpret your interval in context, then an