Mock Exam Business Statistics I Fall 2024 PDF

Mock Exam Fall 2024 Business Statistics I XXXXXX XXXX The exam has two parts. Part I has 10 multiple choice que...

Mock Exam Fall 2024 Business Statistics I XXXXXX XXXX The exam has two parts. Part I has 10 multiple choice questions and Part II has 6 problems that you need to solve. Part I: Identify the letter of the choice that best completes the statement or answers the question. 1. Which measure of central location is meaningful when the data are interval? a. The mean. b. The median. c. The mode. d. All of these choices are meaningful for interval data. 2. A cable company plans to survey potential customers in a small city currently served by satellite dishes. The company randomly selected a sample of 50 city blocks and surveyed every family living on those blocks. What is the statistical name for the sampling technique used? a. Stratified random sampling. b. Cluster sampling. c. Simple random sampling. d. None of the above. 3. A politician who is running for the office of governor of a state with 4 million registered voters commissions a survey. In the survey, 54% of the 5,000 registered voters interviewed say they plan to vote for her. The population of interest is: a. the 4 million registered voters in the state. b. the 5,000 registered voters interviewed. c. the 54% who plan to vote for her. d. all the residents of the state. 4. The Empirical Rule states that the approximate percentage of measurements in a data set (providing that the data set has a bell shaped distribution) that fall within two standard deviations of their mean is: a. 68%.  b. 75%. c. 95%. d. 99%. 5. Which of the following is a correct statement? a. The range is the square root of the variance. b. Two data sets with the same range will have the same variance. c. The range is a measure of variability. d. More data is used to calculate a range than a variance. 6. When two variables tend to move in the same direction, yet still form a linear pattern, how do you describe their relationship? a. A positive linear relationship. b. A negative linear relationship. c. A proportional inverse relationship. d. None of these choices. 7. Which of the following describes the shape of the histogram below? a. Positively skewed b. Negatively skewed c. Symmetric d. None of these choices. 8. Which of the following causes non-sampling error? a. Taking a random sample from a population instead of studying the entire population. b. Making a mistake in the process of collecting the data. c. Selection bias. d. b and c. 9. Which of the following situations is best suited for a pie chart? a. The number of dollars spent this year on each category of final goods. 2  b. The percentage of a charitable donation that goes to administrative costs vs. directly to the charity. c. The number of students in your class who received an A, B, C, D, F on their exam. d. All of these choices are true. 10. Below is the pie graph showing mother tongue of people in a society. Total number of people in society is 1500. How many people speak Marathi? a) 255 b) 270 c) 390 d) 585 3 Part II: Solve the following five problems. Show all the steps in your work. Problem 1 The following data represent the salaries (in thousands of dollars) of a sample of 10 employees of a firm: 10, 15, 13, 11, 10, 10, 15, 20, 15, 21. a. Calculate the mean, median, and mode. b. Calculate the range, variance, standard deviation, and coefficient of variation. c. Describe the shape for the given set of data. 4 5 Problem 2 The grades of a Math exam have a mean of 80 and a variance of 4. If the distribution of grades is positively skewed, a. Find the range of grades (interval) and the percentage (proportion) of grades that fall within two standard deviations from the mean. b. Find the percentage (proportion) of grades that fall within five standard deviations from the mean. 6 Problem 3 The following is a set of data from a sample of n = 6: 9 6 7 11 3 15 a. Calculate the first quartile (Q1), the third quartile (Q3), and the interquartile range. b. Find and list the five-number summary. c. Draw a boxplot and describe the shape of the data. 7 Problem 4 Consider the following sample data: X 8 6 4 2 Y 0 5 8 15 a. Compute the covariance between X and Y. b. Compute the coefficient of correlation between X and Y. c. Based on your answer in part b, describe the direction and the strength of the relationship between X and Y. 8 Problem 5 A survey of commercial buildings served by the Cincinnati Gas & Electric Company asked what main heating fuel was used and what year the building was constructed. A partial contingency table of the findings follows. Fuel Type Construction Electricity Natural Oil Propane Other Total Period Gas Period 1 10 20 30 50 10 Period 2 20 40 60 100 20 Period 3 30 60 90 150 30 Period 4 40 80 120 200 40 Total a. Complete the contingency table by showing the row totals and column totals. b. Prepare a contingency table showing row percentages. c. Describe the relationship between construction period and fuel type. Justify your answer. 9 Problem 6 The ages (in years) of a sample of 25 teachers are as follows: 55 31 25 27 33 29 25 31 36 29 35 35 36 32 38 46 46 42 44 46 39 41 48 54 22 a. Organize these ages as an ordered array. b. Divide the data into 5 classes and then fill out the table below. (3 marks) Class Frequency Relative Frequency Cumulative Relative Frequency (in years) c. Around which class grouping, if any, are these ages concentrated? Explain. 10 11