HW 1 - Bus Stat. Student:

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1 HW 1 - Bus Stat Student: 1. An identification of police officers by rank would represent a(n) level of measurement. A. Nominative C. Interval D. Ratio 2. A(n) variable is a qualitative variable such that there is no meaningful ordering or ranking of the categories. A. Ratio C. Nominative D. Interval 3. Temperature (in degrees Fahrenheit) is an example of a(n) variable. A. Nominative C. Interval D. Ratio 4. A person's telephone area code is an example of a(n) variable. A. Nominative C. Interval D. Ratio 5. A population is a set of existing units. True False 6. Statistical inference is the science of using a sample of measurements to make generalization about the important aspects of a population of measurements. True False 1

2 7. The US local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals. The stem-and-leaf plot of the data for one year is below: In developing a histogram of these data, how many classes would be used? A. 4 B. 5 C. 6 D. 7 E When developing a frequency distribution the class (group), intervals should be A. large. B. small. C. integer. D. mutually exclusive. E. equal. 9. A CFO is looking at how much of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and developed the following stem-and-leaf graph. If a frequency histogram were to be created using these data, how many classes would you create? A. 4 B. 5 C. 6 D. 7 E. 8 2

3 10. All of the following are used to describe quantitative data except the A. Histogram B. Stem and Leaf C. Dot Plot D. Pie Chart 11. can be used to study the relationship between two variables. A. Crosstabulation tables B. Frequency tables C. Cumulative frequency distributions D. Dot plots 12. A plot of the values of two variables is a plot. A. Runs B. Scatter C. Dot D. Ogive plot 13. Which one of the following statistical tools is used with quantitative data? A. Bar chart B. Histogram C. Pie chart D. Pareto chart 14. A bar chart is a graphic that can be used to depict qualitative data. True False 15. According to Chebyshev's theorem, how many standard deviations from the range would include at least 80% of the values? A. 5.0 B. 2.2 C. 2.5 D. 1.6 E A disadvantage of using grouping (a frequency table) with sample data is that: A. Calculations involving central tendency and variation are more complicated than central tendency and variation calculations based on ungrouped data. B. The descriptive statistics are less precise than the descriptive statistics obtained using ungrouped data. C. The interpretation of the grouped data descriptive statistics is meaningless. D. It is much more difficult to summarize the information than it is with the ungrouped data. 3

4 17. If one intends to compare the relative variation between two samples involving two different quantitative variables with different measurement scales, then the most appropriate way is to compare the two samples: A. Standard deviations B. Variances C. Coefficient of variations D. Ranges E. Interquartile ranges 18. When using the Chebyshev's theorem to obtain the bounds for a percent of the values in a population, the interval generally will be the interval obtained for the same percentage if normal distribution is assumed (empirical rule). A. Shorter than B. Wider than C. The same as 19. The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stop watch to record the time they spent in line. The times recorded were as follows (in minutes) 118, 124, 108, 116, 99, 120, 148, 118, 119, 121, 45, 130, 118 What are the inner fences? A , B. 80.5, C , D , E ,

5 In a survey of 550 randomly-selected college statistic students were surveyed on their impressions of their course, instructor and textbook. The results are as follows: Use the above results to answer the following questions: Compute a point estimate of the proportion of all college statistic students who: 20. Think that they had a "very ineffective" instructor A B C D E In a statistic class, 10 scores were randomly selected with the following results were obtained: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66 What is the 10 th percentile? A B C D E

6 22. A(n) is the probability that one event will occur given that we know that another event already has occurred. A. Sample space outcome B. Subjective Probability C. Complement of events D. Long-run relative frequency E. Conditional probability 23. Two mutually exclusive events having positive probabilities are dependent. A. Always B. Sometimes C. Never 24. The of two events X and Y is another event that consists of the sample space outcomes belonging to either event X or event Y or both event X and Y. A. Complement B. Union C. Intersection D. Conditional probability 25. In which of the following are the two events A and B, always independent? A. A and B are mutually exclusive. B. The probability of event A is not influenced by the probability of event B. C. The intersection of A and B is zero. D. P(A B) = P(A). E. B and D. 26. If two events are independent, we can their probabilities to determine the intersection probability. A. Divide B. Add C. Multiply D. Subtract 27. If events A and B are independent, then the probability of simultaneous occurrence of event A and event B can be found with: A. P(A) P(B) B. P(A) P(A B) C. P(B) P(A B)) D. All of the above are correct 6