Directions: You may include the statistical software output, but you must also include a well-written explanation of the findings. Be sure to answer the question asked in each problem, and explain why, with reference to your output. If you calculate the answers manually, be sure to show your work. I would prefer a Word document with your answers below each problem, but you may also submit an Excel document. Do not submit two or more documents.
1: 9.54 Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard deviation of 4.45 pages. (a) At the .01 level of significance, is the true mean greater than 10? (b) Use Excel or MegaStat to find the right-tail p-value.
2: 9.62 The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 orders are processed on the same day, would this prove that they are exceeding their goal, using α = .05?
3. Samsom Polls contends that an agent conducts a mean of 53 in-depth home surveys every week. A streamlined survey form has been introduced, and Samsom wants to evaluate its effectiveness. A random sample of 17 agents showed their total number of surveys conducted during a week.
53 57 50 55 59 54 60 52 59 62 60 51 56 57 60 60 51
At the .05 level of significance, can we conclude that the mean number of interviews conducted by the agents is more than 53 per week? Why? Explain your decision.
sample variance 14.69
sample standard deviation 3.83
confidence interval 95.% lower 54.26
confidence interval 95.% upper 58.21
53.000 hypothesized value
56.235 mean Data
3.833 std. dev.
0.930 std. error
.0015 p-value (one-tailed, upper)
4: Fast Service, a chain of automotive tune-up shops, advertises that its personnel can change the oil, replace the oil filter, and lubricate any standard automobile in 15 minutes, on the average. The National Business Bureau received complaints from customers that service takes considerably longer. To check the Fast Service claim, the Bureau had service done on 21 unmarked cars. The mean service time was 14.5 minutes, and the standard deviation of the sample was 1.5 minute. Use the .05 significance level to check the reasonableness of the Fast Service claim. What would your conclusion be?
Hypothesis Test: Mean vs. Hypothesized Value
15.000 hypothesized value
14.500 mean label
1.500 std. dev.
0.327 std. error
.0711 p-value (one-tailed, lower).
Statistical software output is used for hypothesis testing questions.