MATH 215 INTRODUCTION TO STATISTICS ASSIGNMENT 4 (with workings and corrections) SCORE 98% ATHABASCA UNIVERSITY

Assignment 4
Overview 92
Total marks:
/92
This assignment covers content from Unit 4 of the course. It assesses your knowledge of sampling distributions that refer to probability distributions of sample statistics, such as the sample mean and sample proportion, and your ability to use sampling distributions in estimation and in hypothesis testing about population means and population proportions.
Instructions
Show all your work and justify all of your answers and conclusions, except for the True/False questions.
Keep your work to 4 decimals, unless otherwise stated.
Note: Finishing a test of hypotheses with a statement like "reject Ho" or "do not reject Ho" will be insufficient for full marks. You must also provide a written concluding statement in the context of the problem itself. For example, if you are testing hypotheses about the effectiveness of a medical treatment, you must conclude with a statement like, "we can conclude that the treatment is effective" or "we cannot conclude that the treatment is effective."
(9 total marks)
1. The duration of long-distance telephone calls is normally distributed with a mean of = 18 minutes and a standard deviation of = 12 minutes, If a random sample of 64 telephone calls is used to reflect on the population of all long-distance calls, what is the probability that the sample mean call duration:
(3 marks) = 140-12 n=64