#5 Population Parameters Name___________________________________ PRESENT ALL WORK USING THE 6-STEP TEMPLATE FOR FULL CREDIT 1. Data from a random sample of 35 patients at a medical facility showed that the mean time that the patient took after the scheduled time to see the doctor was 63 minutes with a standard deviation of 58 minutes. Determine the 95% confidence interval for the mean waiting time for all the patients. 2. Determine the 95% confidence interval for the same population with a sample size of 70 patients. 3. What happened to the width of the CI as you doubled the sample size? 1 4. In the testing of a new production method, 18 employees were selected randomly and asked to try the new method. The sample mean production rate of the 18 employees was 80 parts per hour and the sample standard deviation was 10 parts per hour. Assume that the population has a normal probability distribution and construct the 90% CI for the population mean production rate. 5. An opinion poll asks a random sample of 548 adults if "stricter gun control laws are needed." A total of 359 of the 521 respondents said "Yes." Based on this sample, construct a 90% confidence interval to estimate the proportion of people in the general population that favor stricter gun control laws. 2 SAMPLE SIZE Annual starting salaries for college graduates with BA degrees are believed to have a standard deviation of approximately $2000. Assume that a 95% estimate of the mean starting salary is desired. How large a sample should be taken for the following desired margins of error. REMEMBER THAT A SAMPLE SIZE IS A COUNT. a. $500 b. $200 c. $100 3