Provide an appropriate response. 1) Explain what bias there is in a study done entirely online. 1)

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1 Math-150-Exam #1 (Chapter 1, 2 & 3) Name Practice Exam Date: Instructions: Show all work neatly. Answers without support will receive no credit. Your answers will be evaluated on the correctness, completeness and use of mathematical concepts we have covered. Provide an appropriate response. 1) Explain what bias there is in a study done entirely online. 1) Use critical thinking to address the key issue. 2) You plan to make a survey of 200 people. The plan is to talk to every 10th person coming out of the school library. Is there a problem with your plan? 2) 3) An airline company advertises that 100% of their flights are on time after checking 5 randomly selected flights and finding that these 5 were on time. 3) Identify the sampling technique used. 4) Thirty-five sophomores, 50 juniors and 37 seniors are randomly selected from 538 sophomores, 448 juniors and 394 seniors at a certain high school. 4) 5) Every fifth person boarding a plane is searched thoroughly. 5) 6) At a local community college, five statistics classes are randomly selected out of 20 and all of the students from each class are interviewed. 6) Solve the problem. 7) Part A-Construct one table that includes relative frequencies, cumulative frequencies, Midpoints, and Boundaries Relative Cumulative Midpoint Boundaries 7) Part B- Construct a Histogram and Ogive based on the frequency distribution above. 1

2 The Highway Patrol, using radar, checked the speeds (in mph) of 30 passing motorists at a checkpoint. The results are listed below ) Construct a frequency distribution, a relative frequency distribution, and a cumulative frequency distribution using six classes. 8) Relative Cumulative Midpoint Boundaries 9) Construct a histogram and a frequency polygon, using the data above. 9) 2

3 Solve the problem. 10) The scores for a statistics test are as follows: 10) Create a stem-and-leaf display for the data. Construct a pie chart representing the given data set. 11) After reviewing a movie, 300 people rated the movie as excellent, good, or fair. The following data give the rating distribution. Excellent Good Fair ) Construct the dotplot for the given data. 12) The following data represent the number of cars passing through a toll booth during a certain time period over a number of days ) Provide an appropriate response. 13) Use the high closing values of Naristar Inc. stock from the years to construct a time-series graph. (Let x = 0 represent 1990 and so on.) Identify a trend. 13) Year High Year High

4 14) A study was conducted to determine how people get jobs. Four hundred subjects were randomly selected and the results are listed below. 14) Job Sources of Survey Respondents Newspaper want ads 69 Online services 124 Executive search firms 72 Mailings 32 Networking 103 Construct a pie chart of the data. Solve the problem. 15) The data show the total number of medals (gold, silver, and bronze) won by each country winning at least one gold medal in the Winter Olympics. Find the mean, median, and mode of the numbers of medals won by these countries. 15) ) The top speeds for a sample of five new automobiles are listed below. Calculate the standard deviation of the speeds. Round to four decimal places. 16) 115, 185, 170, 175, 145 Data X - X (X-X) 2 4

5 Provide an appropriate response. 17) The test scores of 30 students are listed below. Find the five-number summary. 17) ) The test scores of 30 students are listed below. Find P30. 18) ) Find the z-score for the value 55, when the mean is 58 and the standard deviation is 3. 19) 20) Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean and standard deviation of the test scores are 72 and 5, respectively, and the distribution of scores is bell-shaped and symmetric. Suppose the trainee in question received a score of 68. Compute the trainee's z-score. 20) Determine which score corresponds to the higher relative position. 21) Which is better, a score of 92 on a test with a mean of 71 and a standard deviation of 15, or a score of 688 on a test with a mean of 493 and a standard deviation of 150? 21) 5