Quiz 7 Quiz 9 Questions Answers

5/17/2018 a) 0.7210 b) 0.0569 c) 0.4790 d) 0.2790 e) 0.5580 f) None of the above Question 13 Suppose that a random sample of size 25 is to be selected from a population with mean 44 and standard deviation 7. What is the approximate probability that X will be more than 0.5 away from the population mean? a) 0.2790 b) 0.0569 c) 0.4790 d) 0.7210 e) 0.5580 f) None of the above Question 14 Lloyd's Cereal company packages cereal in 1 pound boxes (16 ounces). A sample of 64 boxes is selected at random from the production line every hour, and if the average weight is less than 15 ounces, the machine is adjusted to increase the amount of cereal dispensed. If the mean for 1 hour is 1 pound and the standard deviation is 0.2 pound, what is the probability that the amount dispensed per box will have to be increased? a) 0.9938 b) 0.3773 c) 0.2062 d) 0.0062 e) 0.0124 f) None of the above 5/6 5/17/2018 Question 15 In a large population, 92% of the households have cable tv. A simple random sample of 64 households is to be contacted and the sample proportion computed. What is the mean and standard deviation of the sampling distribution of the sample proportions? a) mean = 0.92, standard deviation = 1.2739 b) mean = 0.92, standard deviation = 0.0012 c) mean = 0.92, standard deviation = 0.0339 d) mean = 58.88, standard deviation = 0.0339 e) mean = 58.88, standard deviation = 0.0012 f) None of the above Question 16 In a large population, 67% of the households have cable tv. A simple random sample of 256 households is to be contacted and the sample proportion computed. What is the probability that the sampling distribution of sample porportions is less than 73%? a) 0.0206 b) 0.4897 c) 0.9794 d) 0.8796 e) 0.1204 f) None of the above 6/6 5/17/2018 Quiz 7 Question 1 Which of the following would be the scatterplot for the given data? x y 4 21 7 29 8 29 12 42 14 28 18 41 a) 1/7 5/17/2018 b) c) 2/7 5/17/2018 d) e) None of the above Question 2 What can be said about the relationship between the explantory variable and the response variable in the following scatterplot? 3/7 5/17/2018 a) There is a strong negative linear association. b) There is a strong positive linear association. c) There is a weak positive linear association. d) The explanatory variable causes the responses. e) None of the above Question 3 Determine the correlation coefficient for the data shown in this table: x y a) -0.9751 b) -0.9508 c) 0.9508 d) 0.9751 e) -0.4875 f) None of the above 3 43 8 37 10 28 14 22 16 20 17 12 Question 4 Choose the best correlation coefficient for the data shown in this scatterplot: 4/7 5/17/2018 a) -0.9028 b) -0.4514 c) -1.7058 d) 0.4514 e) 0.9028 Question 5 Which of the following is a true statement? a) A negative correlation indicates that as values of x decrease, values of y will decrease. b) The coefficient of determination can never assume negative values. If there is no correlation between the independent and dependent variables, then the value of the c) correlation coefficient must be -1. d) The correlation coefficient r is always greater than 1. e) The variable that is being predicted in regression analysis is the independent variable. f) None of the above 5/7 5/17/2018 Question 6 The decline of salmon fisheries along the Columbia River in Oregon has caused great concern among commercial and recreational fishermen. The paper 'Feeding of Predaceous Fishes on Out-Migrating Juvenile Salmonids in John Day Reservoir, Columbia River' (Trans. Amer. Fisheries Soc. (1991: 405-420)) gave the accompanying data on y = maximum size of salmonids consumed by a northern squaw fish (the most abundant salmonid predator) and x = squawfish length, both in mm. Use the following statistics to give the equation of the least squares regression line. x = 525.060, y = 319.607, sx = 17.908, sy = 14.300, r = 0.9768 a) ŷ = 1.223x − 89.940 b) ŷ = 1.223x + 89.940 c) ŷ = -89.940x + 0.780 d) ŷ = 0.780x + 89.940 e) ŷ = 0.780x − 89.940 f) None of the above Question 7 Suppose that you are given the following results. Find the correlation coefficient of the data. sx = 4.866, sy = 11.100, b = -1.800 a) -0.789 b) 0.789 c) -0.395 d) -0.267 e) 0.267 f) None of the above Question 8 Suppose you find that the correlation coefficient for a set of data is 0.855. What is the coefficient of determination and what does it mean? a) 0.855; This means that we are 85.5% accurate with our prediction of the LSRL equation. 6/7 5/17/2018 b) 0.731; This means that we are 73.1% accurate with our prediction of the LSRL equation. c) 0.855; This means that 85.5% of the variation of y is explained by the LSRL of y on x. d) 0.731; This means that 73.1% of the variation of y is explained by the LSRL of y on x. e) None of the above Question 9 A real estate agent would like to predict the selling price of a single-family house by predicting the price (in thousands of dollars) based on the square footage (in 100 square feet). If the LSRL for the data is ŷ = 3.8785x + 18.3538, predict the price of a 3000 square foot house (in thousands of dollars). tbl a) 139.709 b) 242.709 c) 134.709 d) 252.709 e) 673.544 f) None of the above Question 10 Select the equation of the least squares line for the data: (51.00, 1.0), (48.75, 2.5), (52.50, .5), (46.50, 5.0), (45.00, 4.5), (41.25, 6.5), (43.50, 5.0). a) ŷ = 28.956 − 0.59474x b) ŷ = 31.852 − 0.59474x c) ŷ = 0.54067x − 28.956 d) ŷ = -28.956 − 0.54067x e) ŷ = 28.956 − 0.54067x f) None of the above 7/7 5/17/2018 PRINTABLE VERSION Quiz 8 Question 1 Which of the following would be the LSRL for the given data? x y a) ŷ= b) ŷ= c) ŷ= d) ŷ= e) None of the above 5 41 5 37 11 28 12 21 15 17 19 14 Question 2 Determine the correlation coefficient for the data shown in this table: x y a) -0.9352 b) 0.9352 c) 0.8746 d) -0.8746 e) -0.4676 f) None of the above 1 41 8 38 9 28 12 20 17 18 20 14 Question 3 Suppose you have the following data: 1/8 5/17/2018 x y and the LSRL is ŷ = 1 44 2 37 3 27 4 21 5 22 6 14 . Find the residual value for x = 1. a) b) c) d) e) None of the above Question 4 Which of the following is the residual plot for the data in the given table? x y 1 16 2 20 3 18 4 31 5 24 6 32 a) 2/8 5/17/2018 b) c) 3/8 5/17/2018 d) e) None of the above Question 5 Which of the following residual plots would indicate a good LSRL model? a) 4/8 5/17/2018 b) c) 5/8 5/17/2018 d) Question 6 For children between the ages of 18 months and 29 months, there is approximately a linear relationship between height and age. The relationship can be represented by ŷ = 62.55 + 0.62x where y represents height (in centimeters) and x represents age (in months). Joseph is 23.5 months old and is 80 centimeters tall. What is Joseph's residual? a) 2.880 b) 77.120 c) 7.880 d) 112.150 e) -32.150 f) None of the above Question 7 If the LSRL relating the independent variable x and the dependent variable y for a given problem is ŷ = 2x + 4, then an increase of 1 unit in x is associated with an increase of how many units in y? a) 6 b) 0 6/8 5/17/2018 c) 2 d) 1 e) 4 Question 8 If the correlation between body weight and annual income were high and positive, we could conclude that: a) high incomes cause people to eat more food. high-income people tend to spend a greater proportion of their income on food than low-income b) people. c) high incomes cause people to gain weight. d) high-income people tend to be heavier than low-income people. e) low incomes cause people to eat more food. Question 9 The following two-way table describes the preferences in movies and fast food restaurants for a random sample of 100 people. McDonalds Iron Man 20 Dispicable Me 11 Harry Potter 6 Taco Bell 13 9 14 Wendy's 7 8 12 What percent of people in the sample like the movie Harry Potter? a) 27% b) 40% c) 36% d) 32% e) 37% Question 10 The following two-way table describes the preferences in movies and fast food restaurants for a random sample of 100 people. McDonald's Taco Bell Wendy's 7/8 5/17/2018 Iron Man 20 Dispicable Me 12 Harry Potter 9 15 7 11 5 9 12 What percent of the Dispicable Me lovers also like McDonald's? a) 43% b) 40% c) 9% d) 22% e) 21% 8/8 5/17/2018 Quiz 9 Question 1 Identify the population of interest in the following situation: In order to assess the membership's attitudes about a new Supreme Court decision, a local bar association selects a SRS of 100 lawyers from its membership list. Surveys are delivered to the selected lawyers. 63 of the lawyers return their surveys. a) Lawyers who returned the survey. b) The entire membership of the local bar association. c) The Supreme Court. d) The 100 lawyers surveyed. e) All lawyers. Question 2 Define: voluntary response a) population is divided into similar groups and a SRS is chosen from each group. b) the explanatory variable(s) in an experiment. c) people who choose themselves for a sample by responding to a general appeal. d) choosing the individuals easiest to reach. e) directly holding extraneous factors constant. f) gives each member of the population a known chance to be selected. g) using extraneous factors to create similar groups. h) successively smaller groups are selected within the population in stages. i) every possible sample of a given size has the same chance to be selected. Question 3 Define: stratified random sample a) population is divided into similar groups and a SRS is chosen from each group. 1/4 5/17/2018 b) successively smaller groups are selected within the population in stages. c) directly holding extraneous factors constant. d) the explanatory variable(s) in an experiment. e) every possible sample of a given size has the same chance to be selected. f) using extraneous factors to create similar groups. g) choosing the individuals easiest to reach. h) people who choose themselves for a sample by responding to a general appeal. i) gives each member of the population a known chance to be selected. Question 4 Define: blocking a) people who choose themselves for a sample by responding to a general appeal. b) using extraneous factors to create similar groups. c) the explanatory variable(s) in an experiment. d) choosing the individuals easiest to reach. e) gives each member of the population a known chance to be selected. f) directly holding extraneous factors constant. g) successively smaller groups are selected within the population in stages. h) population is divided into similar groups and a SRS is chosen from each group. i) every possible sample of a given size has the same chance to be selected. Question 5 True or false: Questionnaires with non-neutral wording are likely to have response bias. a) True b) False Question 6 True or false: In an experiment we impose a treatment on the subjects. 2/4 5/17/2018 a) True b) False Question 7 Identify the type of sampling used in the following situation: To judge the appeal to American adults of a proposed television sitcom, a sample of 10 people from each of three different age groups was selected and those chosen were asked to rate a pilot show. a) Voluntary Response b) Stratified Random Sample c) Simple Random Sample d) Convenience Sample Question 8 A personnel director at a large company studied the eating habits of employees by watching the movements of a selected group of employees at lunchtime. The purpose of the study was to determine the proportion of employees who buy lunch in the cafeteria, bring their own lunches, or go out to lunch. If the director includes only the employees in the department nearest her office in her study, she is performing a(n) a) convenience sample b) simple random sample c) quota sample d) stratified random sample e) None of the above Question 9 You are going to test two new varieties of fish food vs. a commonly used fish food. You set up an experiment as follows: 60 fish are randomly assigned to each of three different tanks. One tank is randomly selected to receive one of the new foods and another to receive the other new food. The remaining tank will receive the commonly used food. Fish growth is measured over time. This is an example of: a) a randomized block design. b) a completely randomized design with no control group. c) a completely randomized design with a control group. d) a double blind matched pairs design. 3/4 5/17/2018 e) None of the above Question 10 A game of chance is based on rolling a die two times in succession. The player wins if the larger of the two numbers is greater than 3. Which of the following situations would simulate 8 plays of this game? a) Choosing 48 digits from the random number table (discarding 0,7,8, and 9). b) Choosing 2 single digits from the random number table (discarding 0,7,8, and 9). c) Choosing 8 pairs of single digits from the random number table (discarding 0,7,8, and 9). d) Choosing 8 digits from the random number table (discarding 0,7,8, and 9). e) None of the above 4/4