1) The following table shows percentage rates of return over a year for a sample of 15 common stock mutual funds. Calculate and describe the coefficient of skewness. a. 0.55 and positively skewed. b. -0.48 and negatively skewed. c. 0.55 and negatively skewed. d. 0.48 and positively skewed. 2) The starting salaries of individuals with an MBA degree is normally distributed with a mean of $45,000 and a standard deviation of $5,500 What percentage of MBA's will have starting salaries within $2,900 of the mean? a. 0.4020 b. 0.2010 c. 0.2680 d. -0.1757 3) If you are constructing a confidence interval for a single mean, the confidence interval will ____ with a decrease in the sample size. a. decrease b. increase c. stay the same d. increase or decrease, depending on the sample data 4) Which of the following is NOT an implication of the Central Limits Theorem a. normal sampling distribution b. Mean of sampling distribution equals the population mean c. regardless of the shape of the population, the sampling distribution will be normal d. the standard deviation of the sampling distribution equals the population standard deviation 5) Mark Johnson, Bank of America branch manager, is concerned with the time that the customers wait in line to make a bank transaction during the noon to 1 p.m. lunch hour. He is interested to compute a 99% confidence interval for the time that a customer waits in the line to make a bank transaction. What would be the minimum sample size that he should use for his study if he wants to estimate the waiting time within 1.1 minutes of the actual waiting time considering that historically the average waiting time has been 5.4 minutes and standard deviation of 2.1 minutes? a. 24 b. 26 c. 22 d. 30 6) The weight of a USB flash drive is 30 grams and is normally distributed. Periodically, quality control inspectors at Dallas Flash Drives randomly select a sample of 17 USB flash drives. If the mean weight of the USB flash drives is too heavy or too light, the machinery is shut down for adjustment. Consider the null and alternative hypotheses for this problem. These hypotheses: a. Indicate a one-tail test with a rejection area in the right tail. b. Indicate a one-tailed test with a rejection area in the left tail. c. Indicate a non-directional test with rejection area in the right and left tails. d. Indicate a directional test with rejection area in the right and left tails. 7) A hole-punch machine is set to punch a hole 1.84 centimeter in diameter in a strip of sheet metal in a manufacturing process. The strip of metal is then creased and sent on to the next phase of production, where a metal rod is slipped through the hole. It is important that the hole be punched to the specified diameter of 1.84 cm. To test the punching accuracy, technicians randomly sampled 12 punched holes and measured the diameters. The data (in centimeters) follow. Use an alpha of 10% to determine whether the holes are being punched an average of 1.84 cm. Assume the punched holes are normally distributed. What conclusion you can draw from your hypothesis testing? a. Since P-value = 0.07, we are going to reject the null hypothesis. The machine does not meet the accuracy requirements. b. Since P-value = 0.14, we have failed to reject the null hypothesis. The machine meets the accuracy requirements. c. Since P-value = 0.07, we have failed to reject the null hypothesis. The machine meets the accuracy requirements. d. Since P-value = 0.14, we are going to reject the null hypothesis. The machine does not meet the accuracy requirements. 8) The number of degrees of freedom needed to construct 90% confidence interval for the difference between means when the data are gathered from paired samples, with 15 observations in each sample, is: a. 30 b. 15 c. 28 d. 14 9) Guitars R. US has three stores located in three different areas. Random samples of the sales of the three stores (in $1000) are shown below. The null hypothesis is to be tested at 95% confidence. Determine the p-value and use it for the test Store 1 Store 2 Store 3 80 85 79 75 86 85 76 81 88 89 80 80 a. p-value = 0.85 > 5%. Failed to reject the null hypothesis. There is no evidence of significant difference. b. p-value = 0.458 >5%. Failed to reject the null hypothesis. There is no evidence of significant difference. c. p-value = 0.458 <5%. Reject the null hypothesis. There is evidence of significant difference. d. p-value = 0.085 > 5%. Failed to reject the null hypothesis. There is evidence of significant difference. 10) To test whether or not there is a difference between treatments A, B, and C, a sample of 12 observations has been randomly assigned to the 3 treatments. You are given the results below. Treatm ent Observati on A 2 30 0 2 3 5 3 B 2 26 2 2 2 0 8 C 4 30 0 2 2 8 2 The null hypothesis is to be tested at the 1% level of significance. The p-value is a. 0.386 b. 1.06 c. 0.865 d. 0.24 11) The shape of a chi-square distribution: a. is symmetric b. is skewed to the left c. is skewed to the right d. depends on the sample data 12) Is the type of car purchased in Oakland county independent of the age of the driver? A random sample of 309 car purchases at two different new car dealerships in Oakland county is taken, resulting in the following contingency table of observed values. 21< age < 34 Comp act Midsize Lux ury 26 95 18 35 < age < 55 41 40 20 age > 55 24 13 32 Use = 0.01, what conclusion should be drawn? A. P-value is greater than 1%. Reject null hypothesis, car purchases in Oakland county is independent of the age of the driver B. P-value is less than the 1%. Reject null hypothesis, car purchases in Oakland county is dependent on the age of the driver C. P-value is less than the 1%. Fail to reject null hypothesis, car purchases in Oakland county is independent of the age of the driver D. P-value is greater than 1%. Fail to reject null hypothesis, car purchases in Oakland county is dependent on the age of the driver E. None of the above answer is correct 13) The independent variable is which of the following? a. The predictor variable b. The measure of the manipulation. c. The criterion variable. d. None of the above. 14) You are interested to see if you can predict the price of a book based on its number of pages. You have collected the following information. Using 5% level of significance, can you determine if there is a significant relationship between price and number of pages of the book? Based on what? Book Pages Price ($) A 500 7.00 B 700 7.50 C 750 9.00 D 590 6.50 E 540 7.50 F 650 7.00 G 480 4.50 a. Yes there is a significant relationship since F=6.44 > 1 b. Yes there is a significant relationship since p-value = 0.680 > 5% c. No there is not a significant relationship since F=6.44 > 1 d. No there is not a significant relationship since p-value = 0.052 > 5%