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UNT DSCI 3710 - Exam1A.FALL 07sol

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A. 3.01B. 1.37*C. 0.005D. 0.01E. 0.19A. 3.01B. 1.37C. 0.005D. 0.01E. 0.19*A. p > .1B. .05 < p < .10C. .02 < p < .05*D. .01 < p < .02E. p < .01A. Conclude there is insufficient evidence that the average board length is more than 305 cm because the p-value is greater than the significance level.B. Conclude there is evidence that the average board length is less than 305 cm because the p-value is greater than the significance level.C. Conclude that we cannot reject that the average board length is about 305 cm because the p-value is greater than the significance level. *D. Conclude there is insufficient evidence that average board length is about 305 cm because the p-value is less than the significance level.E. Conclude there is evidence that average board length is exactly 305 cm because the p-value is greater than the significance level.A. Ho: the mean amount of insulation eaten is the same for all three types.*B. Ho: the mean amount of insulation eaten is not the same for all three types.C. Ho: the mean amounts of insulation eaten are different for all three types.D. Ho: the mean amount of insulation eaten is the same for types 1 and 2.E. Ho: the mean amount of insulation eaten is the same for types 1 and 3.A. p > .1B. .05 < p < .10C. .025 < p < .05D. .01 < p < .025E. p < .01 *COURSE: DSCI 3710 Print Name: Exam 1 – version A Signature: ***Key*** Fall 2007 Student ID#: INSTRUCTIONS:- Please print your name and student ID number on this exam. Also, put your signature on this exam.- On your scantron PRINT your name and exam version. - You have 75 minutes to complete this exam. The exam is open book, open notes,and open mind. You may use any type of hand calculator but please show all your work on the exam and mark all answers on the scantron. Usage of cell phones, digital cameras, PDAs, and other communication devices is prohibited.- Please DO NOT pull this exam apart. When you have completed the exam, please turn your scantron and exam booklet into your instructor, at the front desk.- Good luck and we wish you well on the exam.Note: Whenever question(s) are connected you may be asked to assume a result (givena value) as an answer for the previous question but this result (value) may or may not be correct. The procedure is set in place to prevent you from losing points on a subsequent question because you made a mistake on some previous question/s.1Use the information given in the following paragraph to answer first five questions. A lumber company is making boards that are specified to be 305 centimeters tall and a population variance of 3.5 centimeters (cm). If the boards are too long they must be trimmed, and if they are too short they cannot be used. A sample of 14 boards is made, and statistical analysis on the data using Excel is shown below. Is there evidence at the 0.01 significance level that the boards are tooshort or too long?t Test for Population Mean cm Number of Observations 14Sample Standard Deviation 3.309161Sample Mean 306.214286Ho:- = 305 Ha:--- 305T* 1.3729892 * P[T ---T*-] two tail0.192976| T Critical |, - = 0.013.01227699% CI for Pop. Mean 303.550197to 308.8783741. What is the alternative hypothesis for testing the residents’ claim?A. Ha: - > 305B. Ha: - - 305*C. Ha: - > 305D. Ha: - < 305E. Ha: - < 3052. What is the calculated test statistic to test the residents’ claim?A. 3.01B. 1.37*C. 0.005D. 0.01E. 0.193. What is the p-value of this test?A. 3.01B. 1.37C. 0.005D. 0.01E. 0.19*24. Suppose the calculated test statistic were 2.30. Which one of the following would best describe the p-value for the test?A. p > .1 B. .05 < p < .10 C. .02 < p < .05*D. .01 < p < .02E. p < .015. Using the provided Excel output, what is the conclusion of the test, conducted at the 0.01 significance level, concerning the length of the boards and the reason for the conclusion? A. Conclude there is insufficient evidence that the average board length is more than 305 cm because the p-value is greater than the significance level. B. Conclude there is evidence that the average board length is less than 305 cm because the p-value is greater than the significance level.C. Conclude that we cannot reject that the average board length is about 305 cm because the p-value is greater than the significance level. *D. Conclude there is insufficient evidence that average board length is about 305 cm because the p-value is less than the significance level.E. Conclude there is evidence that average board length is exactly 305 cm because the p-value is greater than the significance level. 3Use the information given in the next paragraph to answer the next four questions.A Denton restaurant manager claimed that her 10 waiters could improve their tips if they followedthe 12 DOs and 5 DON’Ts suggested at the Make-Better-Tips Web site (www.make-better-tips.com). The table below shows the average tip amounts (measured in customer check percentage units) from two selected days, before and after the waiters attended training on the DOs and DON’Ts. Results of the analysis at the 5% level of significance are also shown below.Waiter Before After t-Test: Paired Two Sample for Means1 15 14.12 12.5 12.3 Before After3 11.8 13.5 Mean 13.24 13.114 13.2 13.1 Variance 0.851556 0.9454445 13.6 13.5 Observations 10 106 13.1 13.4 Pearson Correlation 0.6211417 14 14.4 Hypothesized Mean Difference 08 13.8 13.5 df 99 13.1 12.1 t Stat 0.49767410 12.3 11.2 P(T<=t) one-tail 0.315323t Critical one-tail 1.833113P(T<=t) two-tail 0.630646t Critical two-tail 2.262157 6. What is the table value of the appropriate test statistic to test the belief that there was an increase in the average tip percentage after the waiters were given the presentation?A. 1.83 * B. 2.26 C. 0.13 D. 0.498 E. 0.3157. What is the calculated value of the appropriate test statistic to test the belief that there was an increase in the average tip percentage after the waiters were given the presentation?A. 1.83 B. 2.26 C. 0.13 D. 0.498* E. 0.3158. What is the p-value for testing the hypothesis that there was an increase in the average tip percentage after the waiters were given the presentation?A. 1.83 B. 2.26 C. 0.13 D. 0.498 E. 0.315*9. What is the point estimate for the mean change in tip percentage (in percentage units) after thepresentation of DOs and DON’Ts?A. 1.83 B. 2.26 C. 0.13* D. 0.498 E. 0.3154Use the following paragraph for the next four questions.A university librarian is


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