The ________ of a variable is computed by determining the sum of all the values of the variable in the data set and dividing this sum by the number of observations in the data set.
A) Arithmetic mean B) Mode C) Geometric mean D) Median
Q. 2Find the z-score for which the area under the standard normal curve to its right is 0.70.
A) -0.81 B) -0.47 C) -0.53 D) -0.98
Q. 3Find the z-score for which the area under the standard normal curve to its right is 0.07.
A) 1.26 B) 1.39 C) 1.48 D) 1.45
Q. 4The U.S. Department of Labor and Statistics wanted to compare the results of an unemployment program for the past two months in the U.S. Two months ago, 7420 people out of a random sample of 143,000 were unemployed.
Last month, 7242 people out of a random sample of 142,000 were unemployed. Construct a 99 confidence interval for the difference between the unemployment rates two months ago and last month.
A) -0.0012 to 0.0030 B) -0.0010 to 0.0028 C) -0.0005 to 0.0022 D) -0.0007 to 0.0025
Q. 5The incomes of trainees at a local mill are normally distributed with a mean of 1,100 and a standard deviation 150. What percentage of trainees earn less than 900 a month?
A) 90.82 B) 35.31 C) 9.18 D) 40.82
Q. 6Researchers wanted to determine whether there was an association between city driving and stomach ulcers. They selected a sample of 900 young adults and followed them for a twenty-year period.
At the start of the study none of the participants was suffering from a stomach ulcer. Each person kept track of the number of hours per week they spent driving in city traffic. At the end of the study each participant underwent tests to determine whether they were suffering from a stomach ulcer. The researchers analyzed the results to determine whether there was an association between city driving and stomach ulcers.
A) cohort; Individuals are observed over a long period of time.
B) retrospective; Individuals are asked to look back in time.
C) cross-sectional; Information is collected at a specific point in time.
Q. 7The weight loss franchise home office wanted to compare the results of two centers. Of 200 randomly selected participants from center A, 152 lost at least 10 pounds. Of 140 randomly selected participants from center B, 109 lost at least 10 pounds.
Construct a 98 confidence interval for the difference between the proportions of participants at center A and participants at center B who lost at least 10 pounds.
A) -0.1093 to 0.0722 B) -0.1378 to 0.1007 C) -0.1264 to 0.0893 D) -0.0947 to 0.0576
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