ECON 2110 Dr. Martin Gritsch Assignment 1 A reminder about Academic Integrity from the syllabus: Violations of the Academic Integrity Policy (a.k.a. cheating in its various forms) will be severely punished. The minimum penalty is a grade of zero on the assignment in question, but it can go up to expulsion from the university. If you have not done so yet, please familiarize yourself with the Academic Integrity Policy (available online at http://www.wpunj.edu/dotAsset/230122.pdf). All parts of that Policy are relevant and important, but for the online setting of the class, I especially would like to stress sections II.B. (on plagiarism) and II.C. (on collusion). Please make sure that you truly understand what all parts of the policy mean. To name a few examples, working together with another student on an assignment, getting help on an assignment from someone else (e.g., a tutor), and copying another student's work are all violations of the Academic Integrity Policy. *** There are three questions on two pages, worth a total of 25 points. *** Question 1 (11 points) Part (a) (4 points) Chicken Delight claims that the mean wait time for an order is 7 minutes or less. A sample of 50 orders revealed a mean wait time of 7.2 minutes. The standard deviation is 1 minute. Using a level of significance of 0.05, carry out a hypothesis test for Chicken Delight's claim. Part (b) (3 points) Chicken Delight claims that the mean wait time for an order is 7 minutes or less. A sample of 200 orders revealed a mean wait time of 7.2 minutes. The standard deviation is 1 minute. Using a level of significance of 0.05, carry out a hypothesis test for Chicken Delight's claim. Part (c) (2 points) Compare your results from Parts (a) and (b) and provide a mathematical explanation for what you find. Part (d) (2 points) Compare your results from Parts (a) and (b) and provide an intuitive explanation for what you find, i.e., why does it make sense that the different sample sizes would change the outcome of the hypothesis test when the rest of the information is unchanged? Page 1 of 3 Page 2 of 3 Question 2 (6 points) Suppose that you want to test the claim that the mean thickness of an iPad screen is 2.5 millimeters. You collect a sample of 80 iPads to carry out a hypothesis test, using a significance level (alpha) of 0.05. Your decision is to not reject the null hypothesis. Part (a) (3 points) Using the information above, what is the smallest possible p-value for this scenario? Part (b) (3 points) Using the information above, what is the largest possible p-value for this scenario? Question 3 (8 points) Part (a) (4 points) The following information is given: - The null hypothesis is that the mean weight of a niffler is 3.5 ounces. The sample mean is 3.1 ounces and the sample standard deviation is 0.4 ounces. The test statistic has a standard normal distribution (if H0 is true). If it is possible to determine the critical value(s) based on this information, determine it/them. If it is not possible, explain why it is not possible. Part (b) (4 points) Part (b) is independent from Part (a), i.e., do not use information from Part (a) to answer Part (b). The following information is given: - The sample consists of 212 cars driving on I-95. Their mean speed is 64 miles per hour. The significance level is 0.01. The test statistic has a standard normal distribution (if H0 is true). If it is possible to determine the critical value(s) based on this information, determine it/them. If it is not possible, explain why it is not possible. Page 3 of 3