Practice Exam 1 STCC204

Transcription

1 Practice Exam 1 STCC204 The following are the types of questions you can expect on Exam 1. There are 24 questions on this practice exam, so it should give you a good indication of the length of the exam. On Exam 1 the 25 th question will be Turn in your crib sheet with your exam paper. With only 24 questions, it is not possible to address all of the topics we covered. You need to study your other assignments to be sure you have studied adequately. 1. A researcher has collected the following sample data. The mean of the sample is The range is a. 9 b. 1 c. 3 d For the data given in Problem 1, the variance is a. 75 b c. 9.2 d A manufacturer of steel pipes produces pipes that are supposed to measure 4 inches in diameter. The actual measurements of the pipes are variable, with a mean of 4 inches and a standard deviation of.04 inches. If the distribution of this variable (actual measurements of the pipes) is bell-shaped, approximately % of the pipes will be between 3.92 inches and 4.08 inches. a. 95 b. 89 c. 75 d. 68 e The mean time required to assemble an electronic component used in CD players is 12 minutes, and the standard deviation is 2.1 minutes. From this we can determine that at least % of the assembly times will be between 7.8 minutes and 16.2 minutes. a. 68 b. 94 c. 75 d. 89 e Eye colors of students enrolled in a statistics class are called a. qualitative data b. quantitative data c. label data d. class data ST204 Practice Exam 1 Page 1 of 5

2 6. Fifteen percent of the students in a School of Business Administration are majoring in Economics, 20% in Finance, 35% in Management, and 30% in Accounting. The graphical device(s) that can be used to present these data is (are) a. a line graph b. only a bar graph c. only a pie chart d. both a bar graph and a pie chart 7. The graph at the right shows the gas mileage (in mpg, miles per gallon) for a fleet of cars owned by a corporation. Based on the box plot given, approximately 25% of the cars had gas mileage better than (greater than) what value? a mpg b. 30 mpg c mpg d mpg e. 15 mpg Inferential statistics a. refers to the process of drawing inferences about the sample based on the characteristics of the population b. is the same as descriptive statistics c. refers to the statistical methods used to draw inferences about a population based on sample information d. is the same as a census 9. The 50th percentile is the a. mode b. median c. mean d. third quartile 10. The interquartile range is a. the 50th percentile b. another name for the variance c. the range for the middle 50% of the data values d. the difference between the largest and smallest values ST204 Practice Exam 1 Page 2 of 5

3 11. Paul, a freshman at a local college just completed 15 credit hours. His grade report is presented below. Credit Course Hours Grades Calculus 5 C Biology 4 A English 3 D Music 2 B P.E. 1 A The local university uses a 4 point grading system, i.e., A = 4, B = 3, C = 2, D = 1, F = 0. Compute Paul s semester grade point average. a. 3.0 b. 2.8 c. 2.6 d. 2.4 e A researcher has collected the following sample data The median is a. 6 b. 8 c. 7 d For the data given in Problem 12, the mean is a. 5 b. 6 c. 7 d The notation for a population mean is a. σ b. s c. y d. µ e. None of the above 15. The collection of all possible outcomes in an experiment is a. the sample space b. the sample c. an experiment d. the population e. the distribution ST204 Practice Exam 1 Page 3 of 5

4 16. The weight of an object is an example of a. a continuous random variable b. a discrete random variable c. either a continuous or a discrete random variable, depending on the weight of the object d. either a continuous or a discrete random variable depending on the units of measurement e. a complex random variable 17. In a frequency distribution, the sum of frequencies for all classes will always equal a. 1; b. the number of elements in a data set; c. the number of classes; d. a value between 0 and 1; e A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below. Number of Breakdowns Probability The expected number of machine breakdowns per month is a. 2 b. 1.7 c. 1 d..20 e Refer to problem 18. The probability of at least 3 breakdowns in a month is a. 0.5 b c d Quantitative data a. are always nonnumeric; b. may be either numeric or nonnumeric; c. are always numeric; d. are always labels; e. are also called qualitative ST204 Practice Exam 1 Page 4 of 5

5 21. The difference between a histogram and a frequency polygon is a. the frequency polygon is reported as a percent b. the histogram employs bars whereas the midpoints are connected for a frequency polygon c. bars cannot be adjacent in a histogram d. open-ended classes can be accommodated with a frequency polygon 22. Which of the following measures of central tendency is affected by extreme values? a. mean b. median c. mode d. both the mean and median e. the mean, median and mode are all affected by extreme values 23. When we find the probability of an event happening by subtracting the probability of the event not happening from 1, we are using a. subjective probability; b. the complement rule; c. the special rule of addition; d. the special rule of multiplication; e. the subtraction rule 24. A market survey of homeowners in the Southeast indicates that 30% of homeowners use a push mower to mow their lawn, 40% of homeowners use a riding lawn mower, while 10% use both type of mowers. From this information, we know that the events use a push mower and use a riding lawn mower are a. mutually exclusive b. collectively exhaustive c. independent d. both mutually exclusive and collectively exhaustive e. none of the above ANSWERS: 1.a; 2.d; 3.a; 4.c; 5.a; 6.d; 7.a; 8.c; 9.b; 10.c; 11.c; 12.a; 13.c; 14.d; 15.a; 16.a; 17.b; 18.b; 19.e(.25); 20.c; 21.b; 22.a; 23.b; 24.e ST204 Practice Exam 1 Page 5 of 5