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Unformatted text preview: OM – 210, Summer A2010, (Prof. Sid Das) HOMEWORK – 2, (68 points) Please answer on a SCANTRON sheet. WRITE YOUR NAME AND CLASS TIME ON THE TOP OF YOUR SCANTRON SHEET. HOMEWORK DUE DATE is June 16, 2010. Problem A The manager of a grocery store claims that the average time that customers spend in checkout lines is 20 minutes or less. A sample of 36 customers is taken. The average time spent on checkout lines for the sample is 24.6 minutes; and the sample standard deviation is 12 minutes. Conduct a hypothesis test (at 0.05 level of significance) to determine if the mean waiting time for the customer population is significantly more than 20 minutes. ANSWER QUESTIONS 1  4. 1. The correct hypotheses for the test are: a. H is: μ ≥ 20; H a is: μ < 20 b. H is: μ ≤ 20; H a is: μ > 20 c. H is: μ > 20; H a is: μ ≤ 20 d. H is: μ < 20; H a is: μ ≥ 20 2. The observed value of the test statistic is: a. 2.3 b. 0.38 c.2.3 d. 0.38 3. The pvalue is: a. 0.5107 b. 0.0214 c. 0.0137 d. 0.4893 4. The null hypothesis should: a. not be rejected b. be rejected c. the test is inconclusive d. none of the above answers are correct Problem B A random sample of 16 students selected from the student body of a large university had an average age of 25 years with a standard deviation of 2 years. Conduct a hypothesis test (at 0.05 level of significance) to determine if the average age of the population of students at the university is significantly different from 24 years. Assume that the distribution of the population of ages is normal. BASED ON THIS PROBLEM  ANSWER QUESTIONS 5 THROUGH 7 BELOW. 5. The correct hypotheses for the test are: a. H is: μ ≥ 24; H a is: μ < 24 b. H is: μ ≤ 24; H a is: μ > 24 c. H is: μ is not equal to 24; H a is: μ = 24 d. H is: μ = 24; H a is: μ is not equal to 24. 6. The observed value of the test statistic is: a. 1.96 b. 2.00 c. 1.645 d. 0.05 7. It can be concluded that the mean age of the student population is: a. not significantly different from 24 b. significantly different from 24 c. significantly less than 24 d. significantly less than 25 Problem C: Use the following to answer questions 89: A major airline company is concerned that its proportion of late arrivals has substantially increased in the past month. Historical data shows that on the average 18% of the company airplanes have arrived late. In a random sample of 1,240 airplanes, 310 airplanes have arrived late. If we are conducting a hypothesis test of a single proportion to determine if the proportion of late arrivals has increased: 8. What is the correct statement of null and alternative hypothesis?...
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This note was uploaded on 09/21/2011 for the course OM 210 taught by Professor Singer during the Summer '08 term at George Mason.
 Summer '08
 SINGER

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