Quiz 7 With Answers

Quiz 7 You scored 100 out of 100 Question 1 Your answer is CORRECT. Which of the following would be the scatterplot for the given data? G]@=][IJ[IJ[ill[EJOIJ G]@J[fil[fil[ill[fil[±O 50 40 30 20 1.0 0 a) 5 I 10 I 1.5 I 20 1/8 Print Test 11/10/2014 50 0 40 30 0 20 1.0 b) 0 o-------.-----.--r----r-----.----.--r----r-----.----.--r-------.--� 5 IO 20 1.5 50 0 40 JO 0 20 1.0 0 ----..----.----.----.-,----r-----r----r-r----r-----r----r-r------.----.--� c) 0 0 5 10 20 218 Print Test 11/10/2014 50 40 30 20 1.0 o-��������--���������� 5 IO 1.5 20 e) 0 None of the above Question 2 Your answer is CORRECT. What can be said about the relationship between the explantory variable and the response variable in the following scatterplot? 3/8 Print Test 11/10/2014 200 150 1.00 50 l' , ,,,., ,, , 0 -+----.--..-'----.----.----.-----.---,,--.--..---.----.----.----.----.-----.-----.----,-----.---,---, 5 1.0 15 20 a) 0 There is a weak positive linear association. b) 0 The explanatory variable causes the responses. � @ There is a strong positive linear association. '-7 d) 0 There is a strong negative linear association. e) 0 None of the above Question 3 Your answer is CORRECT. Determine the correlation coefficient for the data shown in this table: 0[D[IJ[TI[DJOIJOIJ [z][ill[fil[fil8Q][fil[ill G) @ 0.6047 b) 0 0.3656 x=c(2,7,8,1 1, 17 ,16) > y=c(23,28,29,40,28,42) > cor(x,y) [ 1] 0 .6046549 4/8 11/10/2014 Print Test c) 0 0.3023 d) 0 -0.3656 e) 0 -0.6047 f) 0 None of the above Question 4 Your answer is CORRECT. Choose the best correlation coefficient for the data shown in this scatterplot: 50 40 JO 20 1.0 o-�������������������� 5 )Q O -0.7483 @ @0.7483 10 20 c) 0 1.4513 � 0 -0.3742 e) 0 0.3742 Question 5 5/8 Print Test 11/10/2014 Your answer is CORRECT. Which of the following is a true statement? £& ......�� ¥ �"'"Ao\ �- S • $. � a) 0 The variable that is being predicted in regression analysis is the independent variable. b) 0 If there is no correlation between the independent and dependent variables, then the value of the correlation coefficient must be -1. €)) @ The correlation coefficient r is always between -1 and +1. d) 0 The coefficient of determination can assume negative values. e) 0 A negative correlation indicates that as values of x decrease, values of y will decrease. f) 0 None of the above Question 6 Your answer is CORRECT. 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: 405420)) 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. l x = 525.180, y = 372.258, sx = 13.431, sy= l2.IO0, r = 0.9768 \'2. ·' a) 0 y b) 0 y = -89.900x + 0.880 c) 0 y = 1.084x - 89.900 d) 0 y = 1.084x + 89.900 = o. q;-c. 8 0.880X + 89.900 @® y = 0.880X - 89.900 f) 0 None of the above \o - o. 8 I 0. � "'j - ' 't . q "l.. J \ 3-61-31 -� :. lL -t\o X � - \C\.ql to. Rt>e. Question 7 Your answer is CORRECT. Suppose that you are given the following results. Find the correlation coefficient of the data. 6/8 Print Test 11/10/2014 lo = a) 00.155 Sy= 13.400, b = -6.480 r l 1\ s" ) b) 0 -0.433 @>® -0.866 d) 00.866 e) 0 -0.155 f) 0None of the above Question 8 Your answer is CORRECT. t Suppose you find that the correlation coefficient for a set of data is -0.824. What is the coefficient of determination and what does it mean? f 11',,\oo 1 o : 0 . 8 2.&t-),_ ,t \oo'11:t a) 0-0.824; This means that we are 82.4% accurate with our prediction of the LSRL equation. b) 0 0.824; This means that 82.4% of the variation ofy is explained by the LSRL ofy onx. c) 00.679; This means that we are 67.9% accurate with our prediction of the LSRL equation. ®® 0.679; This means that 67.9% of the variation ofy is explained by the LSRL ofy onx. e) 0None of the above Question 9 Your answer is CORRECT. Suppose that the LSRL for the appraised value ( in thousands of dollars) and number of rooms for houses in East Meadow, New York is y = 19.7 l 8x + 74.80. Predict the price of a 14 room house (in thousands of dollars). tbl 't) to ; =- l 'I . ':J-- \ i' l • a) 01052.556 b) 0 454.852 -\- �'+ . " _ 3 So. 8S 2.. \1 - c) 0355.852 7/8 Print Test 11/10/2014 d) 0 464.852 @@350.852 f) 0 None of the above Question 10 Your answer is CORRECT. Select the equation of the least squares line for the data: (51.00, 1.30), (48.75, 3.25), (52.50, .65), (46.50, 6.50), (45.00, 5.85), (41.25, 8.45), (43.50, 6.50). x=c(51,48.75,52.5,46.5,45,41. 25,43.5) a) 0 y = 41.407 - 0.77316x > y=c(l .30,3.25,.65,6.50,5.85,8.4 b) 0 y = 37.643 - 0.77316x 5,6.50) > lm(y~x) = 37.643 - 0.70287x @ y G) Call: lm( f01mula = y ~ x) d) 0 y = 0.70287x - 37.643 e) 0 y = -37.643 - 0.70287x f) 0 None of the above Coefficients: (Intercept) x 37.6429 -0.7032 8/8 Print Test 11/10/2014 PRINTABLE VERSION Quiz 8 You scored 100 out of 100 Question 1 Your answer is CORRECT. Which of the following would be the LSRL for the given data? w@JCillCKJOOCEJDIJ GJ[J[D[IJ[ill[JTIOIJ a) Q y = 42.82 + 1.625 X x=c(l ,4,8,12,15,19) > y=c(43,37,26,20,24, 11) > lm(y~x) @)@ y = 42.82 - 1.625 X Call: lm( fonnula = y ~ x) c) o y = -l.625 + 42. d) O y= Coefficients: (Intercept) x 42.815 -1.625 2x -1.625 - 42.82x e) 0 None of the above Question 2 Your answer is CORRECT. Determine the correlation coefficient for the data shown in this table: GJ[D[[J[DJDI]lli]DIJ G][fil[KJ[ill82J[ill[ill a) 0 -0.7019 ®'® 0.7019 x=c(3,6,11,13,l 6, 18) > y=c(22,28,27,40,27,43) > cor(x,y) [1] 0.7018695 c) 0 0.3509 1/9 Print Test 11/10/2014 d) 0 -0.4926 e) 0 0.4926 f) 0 None of the above Question 3 Your answer is CORRECT. Suppose you have the following data: 0[JITJ[IJITJ[IJ[IJ GJ[EJ[fil[fil[ill[ill[±O and the LSRL is y = 21.73 + 3.171 x . Find the residual value for x = l. a) 0 24 {S)@ c) o �L\) - ; L\) :: 2.41- - 241-- c,'I \-:: - 0 .'Io I -o.9m 24.901 d) O 0.9m e) 0 None of the above Question 4 Your answer is CORRECT. Which of the following is the residual plot for the data in the given table? 0[JITJ[IJITJ[IJ[IJ GJ[EJ[J[]OIJ[ill[ill[JIJ x=c(l,2,3,4,5,6) > y=c(14,19,18,32,23,31) > quizline=lrn(y~x) > plot(x,resid( quizline)) 219 Print Test 11/10/2014 4 3 0 2 0 0 3 4 5 6 -1 -2 0 -3 -4 a) 0 -5 0 0 co 0 � 'o�� �&.,(� ""-·"""' a) 0 high incomes cause people to gain weight. \ ( f'. c,..,-M.C. �;. r::- N)Jtr �.-1 ��, b) 0 high incomes cause people to eat more food. t c) 0 high-income people tend to spend a greater proportion of their income on food than low-income people. 719 Print Test 11/10/2014 {1)@ high-income people tend to be heavier th� 1 '17-income people. £_ '�\Jtr (> M � e) 0 low incomes cause people to eat more food. »o Question 9 Your answer is CORRECT. The following two-way table describes the preferences in movies and fast food restaurants for a random sample of 100 people. I II McDonalds IIronMan II 20 IDispicableMell 10 !Harry Potter II 5 Taco Bell 12 11 15 Wendy's 8 7 12 What percent of people in the sample like the movie IronMan? 2.o -t \ 1... °'" a) 0 28% g - 'to 1o 100 \00 b) 0 27% 't,o c) 0 35% d) 0 38% @-!) 40% Question 10 Your answer is CORRECT. The following two-way table describes the preferences in movies and fast food restaurants for a random sample of 100 people. I II McDonald's II 20 !IronMan IDispicableMell 10 !Harry Potter II 9 3'1 Taco Bell 13 11 11 What percent of the IronMan lovers also like Taco Bell? 3S Wendy's 7 7 12 4to 1.g 12. 2.e- a) 0 40% b) 0 11% 8/9 11/10/2014 Print Test c) 0 19% d) 0 24% @@33% 9/9