Answers Questions Quiz 7 Quiz 9

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 11/12/2018 Print Test b) c) 2/7 11/12/2018 Print Test 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 11/12/2018 Print Test a) There is a strong positive linear association. b) There is a strong negative 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) -0.8946 b) 0.4473 c) 0.8946 d) 0.8003 e) -0.8003 f) None of the above 2 22 8 29 8 28 13 40 16 33 19 41 Question 4 Choose the best correlation coefficient for the data shown in this scatterplot: 4/7 11/12/2018 Print Test a) 0.4048 b) -0.4048 c) 1.6126 d) 0.8096 e) -0.8096 Question 5 Which of the following is a true statement? a) A negative correlation indicates that as values of x increase, values of y will decrease. b) The coefficient of determination can 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 11/12/2018 Print Test 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 = 525.150, y = 293.390, sx = 18.795, sy = 14.200, r = 0.9662 a) ŷ = 1.279x − 89.970 b) ŷ = -89.970x + 0.730 c) ŷ = 0.730x − 89.970 d) ŷ = 1.279x + 89.970 e) ŷ = 0.730x + 89.970 f) None of the above Question 7 Suppose that you are given the following results. Find the correlation coefficient of the data. sx = 5.825, sy = 14.100, b = -1.910 a) 0.267 b) -0.395 c) -0.789 d) -0.267 e) 0.789 f) None of the above Question 8 Suppose you find that the correlation coefficient for a set of data is 0.826. What is the coefficient of determination and what does it mean? a) 0.682; This means that we are 68.2% accurate with our prediction of the LSRL equation. 6/7 11/12/2018 Print Test b) 0.682; This means that 68.2% of the variation of y is explained by the LSRL of y on x. c) 0.826; This means that 82.6% of the variation of y is explained by the LSRL of y on x. d) 0.826; This means that we are 82.6% accurate with our prediction of the LSRL equation. 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) 134.709 c) 248.709 d) 252.709 e) 942.962 f) None of the above Question 10 Select the equation of the least squares line for the data: (44.20, 1.30), (42.25, 3.25), (45.50, .65), (40.30, 6.50), (39.00, 5.85), (35.75, 8.45), (37.70, 6.50). a) ŷ = -37.643 − 0.81100x b) ŷ = 37.643 − 0.81100x c) ŷ = 41.407 − 0.89210x d) ŷ = 37.643 − 0.89210x e) ŷ = 0.81100x − 37.643 f) None of the above 7/7 11/12/2018 Print Test PRINTABLE VERSION Quiz 8 Question 1 Which of the following would be the LSRL for the given data? a) ŷ= b) ŷ= c) ŷ= d) ŷ= e) None of the above x 3 5 10 11 17 17 y 43 37 26 21 16 14 Question 2 Determine the correlation coefficient for the data shown in this table: a) -0.7447 b) 0.7447 c) -0.5546 d) 0.3724 e) 0.5546 f) None of the above x 1 4 8 12 15 19 y 23 29 26 41 29 41 Question 3 Suppose you have the following data: 1/8 11/12/2018 Print Test x 1 2 3 4 5 6 y 24 29 28 42 33 41 and the LSRL is ŷ = . 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 11/12/2018 Print Test b) c) 3/8 11/12/2018 Print Test d) e) None of the above Question 5 Which of the following residual plots would indicate a good LSRL model? a) 4/8 11/12/2018 Print Test b) c) 5/8 11/12/2018 Print Test 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 = 62.05 + 0.65x where y represents height (in centimeters) and x represents age (in months). Joseph is 24.5 months old and is 82 centimeters tall. What is Joseph's residual? a) 4.025 b) 115.350 c) 77.975 d) -33.350 e) 7.025 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 = 3x + 4, then an increase of 1 unit in x is associated with an increase of how many units in y? a) 4 b) 1 6/8 11/12/2018 Print Test c) 0 d) 3 e) 7 Question 8 If the correlation between number of children in a family and annual income was close to -1, we could conclude that: a) high incomes cause people to have more children. b) high incomes cause sterility. c) low incomes cause people to have more children. d) high-income families tend to have more children. e) low-income families tend to have more children. 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 12 Harry Potter 7 Taco Bell 14 7 13 Wendy's 6 9 12 What percent of people in the sample like the movie Iron Man? a) 28% b) 34% c) 27% d) 40% e) 39% 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 11/12/2018 Print Test Iron Man 20 14 6 Dispicable Me 12 7 9 Harry Potter 13 12 7 What percent of the Dispicable Me lovers also like McDonald's? a) 19% b) 21% c) 7% d) 40% e) 43% 8/8 11/12/2018 Quiz 9 Question 1 Identify the population of interest in the following situation: A radio talk show wanted to know whether Houstonians think Texas should continue to use the death penalty. The station asked for listeners to call in and give their opinion. a) Listeners of the radio station. b) The population of the United States. c) Houstonians. d) Prisoners. e) Texans. 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) the explanatory variable(s) in an experiment. 1/4 11/12/2018 Print Test b) people who choose themselves for a sample by responding to a general appeal. c) successively smaller groups are selected within the population in stages. d) population is divided into similar groups and a SRS is chosen from each group. e) choosing the individuals easiest to reach. f) gives each member of the population a known chance to be selected. g) every possible sample of a given size has the same chance to be selected. h) using extraneous factors to create similar groups. i) directly holding extraneous factors constant. 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: The entire group of individuals we want information about is called the sample. 2/4 11/12/2018 Print Test a) True b) False Question 7 Identify the type of sampling used in the following situation: A radio talk show wanted to know whether Houstonians think Texas should continue to use the death penalty. The station asked for listeners to call in and give their opinion. a) Convenience Sample b) Stratified Random Sample c) Simple Random Sample d) Voluntary Response 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 selects 50 employees at random from throughout the company and categorizes their lunchtime practices by gender, she is: a) promoting sexual harassment b) testing for bias c) blocking for gender d) testing for a lurking variable e) None of the above Question 9 Suppose you are interested in the effects on boys of different dosages of a new drug to treat ADHD. You set up an experiment to consider the factor of dosage with two levels (300 mg vs. 500 mg). Which would be the best choice for the different treatment groups of the experiment within each block? a) Three groups: no drug, 300 mg of new drug, 500 mg of new drug. b) Two groups: placebo drug and either 300 mg of new drug or 500 mg of new drug. c) Four groups: no drug, placebo drug, 300 mg of new drug, 500 mg of new drug. d) Three groups: placebo drug, 300 mg of new drug, 500 mg of new drug. 3/4 11/12/2018 e) Print Test Two groups: 300 mg of new drug and 500 mg of new drug. 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 10 plays of this game? a) Choosing 10 digits from the random number table (discarding 0,7,8, and 9). b) Choosing 60 digits from the random number table (discarding 0,7,8, and 9). c) Choosing 10 pairs of single digits from the random number table (discarding 0,7,8, and 9). d) Choosing 2 single digits from the random number table (discarding 0,7,8, and 9). e) None of the above 4/4