### QNT 561 Week 1 Practice Quiz My Statslab

1. What is statistics?

2. Explain the difference between descriptive and inferential statistics.

3. Explain the difference between qualitative and quantitative data.

4. Explain how populations and variables differ.

5. Explain how populations and samples differ.

6. What is a representative sample?

7. Explain the difference between a population and a process.

8. Define statistical thinking.

9. Suppose you’re given a data set that classifies each sample unit into one of four categories: A, B, C or D. You plan to create a computer database consisting of these data, and you decide to code the data as A = 1, B = 2, C = 3 and D = 4. Are the data consisting of the classifications A, B, C and D qualitative or quantitative? After the data are in out as 1, 2, 3, or 4, are they qualitative or quantitative?

10. Identify each of the following variables as qualitative or quantitative.

11. Each month interviewers visit about 69,000 of the 93 million households in the region and question the occupants over 18 years of age about their educational status. Their responses enable the interviewers to estimate the percentage of people in the labor force who are college educated. Compare parts a through c.

12. Complete the table to the right?

13. In one university, language professors incorporated a 10-week extensive program to improve students’ Japanese reading comprehension. The professors collected 283 books originally written for Japanese children and required their students to read at least 40 of them as part of the grade in the course. The books were categorized into reading levels (color-coded for easy selection) according to length and complexity. Complete parts a through c.

14. A group of marketing professors asked every fourth adult entrant to a mall to participate in a study. A total of 119 shoppers agreed to answer the question, “Made locally” means what percentage of local labor and materials?” The responses of the 119 shoppers are summarized in the table to the right. Complete parts a through c below.

15. Graph the relative frequency histogram for the 300 measurements summarized in the relative frequency table to the right.

16. If jobs arrive at a particular work center at a faster rate than they depart, the work center impedes the overall production process and is referred to as a bottleneck. The data in the table were collected by an operations manager for use in investigating a potential bottleneck work center.

17. A data set contains the observations 3, 5, 4, 2, 3. Find the following values.

18. Calculate the mean and Median of the following grade point averages.

2.5 2.9 3.6 2.6 3.2 3.7

19. Five banks have been ranked by the amount charged to credit and debit cards issued by the banks. The table to the right gives the total amount charged in 2007 for the top ranked banks.

20. The data on the age (in years) of each of the 20 most powerful women in a region are shown below.

49 62 52 ……………………………………….64

21. The salaries of superstar professional athletes receive much attention in the media. The multimillion-dollar long-term contract is now commonplace among this elite group. Nevertheless, rarely does a season pass without negotiations between one or more of the players’ associations and team owners for additional salary and fringe benefits for all players in their particular sports. Complete parts a and b below.

22. Calculate the range, variance, and standard deviation for the following sample.

3, -3,2,……………….4

23. A university’s language professors incorporated a 10-week extensive redaing program into a second-semester Japanese language course in an effort to improve students’ Japanese reading comprehension. Fourteen students participated in this reading program. Complete parts a through c.

24. A country’s Energy Information Administration monitors all nuclear power plants operating in that country. The table to the right lists the number of active nuclear power plants operating in each of a sample of 10 states.

25. A study of 100,000 first-time candidates for the CPA exam found that the mean number of semester hours of college credit taken by the candidates was 144.58 hours. The standard deviation was reported to be 15.73 hours. Complete parts a through c.

26. Compute the z-score corresponding to each of the values of x below.

27. Compare the z-scores to decide which of the x values below lie the greatest above the mean and the greatest distance below the mean.

28. A sample data set has a mean of 74 and a standard deviation of 10. Determine whether each of the following sample measurements are outliers.

29. Consider the horizandal box shown to the right.

30. Educators are constantly evaluating the efficacy of public schools in the education and training of students. One quantitative assessment of change over time is the difference in scores on the SAT. The table below contains the average SAT scores for 10 states for the years 1988 and 2005.

31. Data on annual rainfall, maximum daily temperature, percentage of planet cover, and number of anti species recorded at each of 11 study sites are given in the accompanying table. Complete parts a through c.

32. Determine whether the random variable is discrete or continuous.

33. The random variable x has the following discrete probability distribution. Complete parts a through f.

34. X intercept, y intercept

35. If x is a binomial random variable, compute p(x) for each of the cases below.

36. According to a business magazine, 30% all small businesses owned by non-Hispanic whites nationwide are women-owned firms.

37. According to a certain golf association, the weight of the golf ball ball shall not be greater than 1.620 ounces (45.93 grams). The velocity of the ball shall not be greater than 250 feet per second. The golf association periodically checks the specifications of golf balls using sampling. Five dozen of each kind are sampled, and if more than three do not meet size or velocity requirements, that kind of ball is removed from the golf association’s approved list. Complete parts a and b.

38. Find the area under the standard normal probability distribution between the following pairs of z-scores.

39. Suppose the random variable x is the best described by a normal distribution with µ = 32 and = 5. Find the z-score that corresponds to each of the following x-values.

40. The mean gas mileage for a hybrid car is 56 miles per gallon. Suppose that the gasoline mileage is approximately normally distributed with a standard deviation of 3.2 miles per gallon.

41. Personnel tests are designed to test a job applicant’s cognitive and/or physical abilities. A particular dexterity test is administered nationwide by a private testing service. It is known that for all tests administered last year, the distribution of scores was approximately normal with mean 76 and standard deviation 7.8.

42. Determine evidence to support or contradict the assumption that the data to the right come from an approximately normal distribution.

43. An airport terminal handles an average of 3,000 international passengers an hour, but is capable of handling twice that number. Also after scanning all luggage, 20% arriving international passengers are detained for intrusive luggage inspection. The inspection facility can handle 500 passengers an hour without unreasonable delays for the travelers. Complete parts a through c.

44. Will the sampling distribution of always be approximately normally distributed? Explain.

45. The number of semester hours of college credit taken by first-time candidates for a certain professional exam has a distribution with a mean of 127 hours and a standard deviation of 14 hours. Consider a random sample of 100 first-time candidates for the exam and let represent the mean number of hours of college credit taken for the sample. Complete parts a through e below.