# Stats Practice Exam

**Topics:**Arithmetic mean, Confidence interval, Average

**Pages:**8 (3113 words)

**Published:**June 23, 2013

2) Find the standard deviation of the data set A) 9.33 B) 522.00 C) 104.40 D) 10.22

3) The five-number summary of the data set consists of __________, __________, __________, __________, and __________. A) -2, 10, 13.5, 23, 26 B) -2, 10, 14.5, 23, 26 C) -2, 1.5, 3, 4.5, 26 D) -2, 10, 14, 23, 26

4) Based on the boxplot, the distribution shape of the data set is A) normal B) bell-shape C) left-skewed D) right-skewed

Question 5-7: The owner of a local nightclub has recently surveyed a random sampled of 81 customers of the club with: X = 21.73, s = 2.8. She would like to determine whether or not the mean age of her customers is over 21. 5) Give the null and alternative hypotheses. A) H0: X ≤ 21.73 and H1: X > 21.73 C) H0: m ≤ 21 and H1: m > 21 B) H0: m = 21 and H1: m ≠ 21 D) H0: m ≥ 21 and H1: m < 21

6) Using the sample information provided, calculate the value of the test statistic. A) t = (21.73-21.00) / (2.8/9) C) t = (21.73-21.00) / 2.8 7) Suppose a = 0.005. Which of the following is correct? A) At a = 0.005, we fail to reject H0. C) No decision should be make B) At a = 0.005, we accept the data. D) At a = 0.005, we reject H0. B) t = (21.73-21.00 ) / ( 2.8/92 ) D) t = (21.00 - 21.73) / ( 2.8/9)

Question 8-9: The following table contains the number of employees of a company over the last five year. Year Number of employees 1999 35 2000 40 2001 45 2002 40 2003 38 8) If a three-term moving average is used for forcasting, what is the forscasting for year 2003? A) 38 B) 40 C) 41.67 D) 41

9) If we want to obtain the exponential smoothing time-series for forcasting, what would be the valus of F4 (use a=0.4)? A) 40.2 B) 45 C) 37 D) 41.8

10) Based on the definition, a wavelike pattern describing a gradual ups and downs movement that is generally apparent over a year would be considered as the __________ pattern. A) cyclical B) seasonal C) trend D) horizontal

Question 11-12: You're a manager of a hotel. You want to achieve the higest level of service. For 10 days, you collect data on the readiness of 100 rooms. Day 1 2 3 4 5 6 7 8 9 10 Total: #Rooms 100 100 100 100 100 100 100 100 100 100 1000 #Not Ready 10 15 10 16 19 16 13 15 11 15 140

11) The p control chart is to be made for these data. The proportion p (the center line) of the control chart is __________. A) 0.150 B) 0.140 C) 0.143 D) 14.00

12) The p control chart is to be made for these data. The upper control limit is __________, and the lower control limit is __________. A) 0.232; 0.0132 B) 0.0864; 0.001 C) 0.249; 0.039 D) 0.244;0.036

Question 13-14: In an article, the authors compare the use of humor in TV ads in the United States and in the United Kingdom. A random sample of 100 TV ads in the United States reveals that 45 use humor, while a random sample of 120 TV ads in the United Kingdom reveals that 35 use humor. Let p1 and p2 represent the true proportion of ads using humor in the United States and in the United Kingdom respectively. If we want to test the claim that the proportions are different, 13) Which of the following represents the hypotheses? A) H0 : p 1 - p 2 ≥ 0 versus H1 : p 1 - p 2 < 0 C) H0 : p 1 - p 2 ≤ 0 versus H1 : p 1 - p 2 > 0 B) H0 : p 1 - p 2 = 0 versus H1 : p 1 - p 2 ≠ 0 D) H0 : p 1 - p 2 ≠ 0 versus H1 : p 1 - p 2 = 0

14) At a = 0.01, if the test statistic is 2.43, which of the following is most correct? A) Fail to reject H0 , there is not enough evidence to conclude that the two proportions are different. B) Fail to reject H0 , there is not enough evidence to conclude that the two proportions are the same. C) Reject H0 . There is enough evidence to conclude that the two proportions are different. D) Reject H0 . There is enough evidence to...

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