Devry MATH221 Week 7 Homework Latest 2020 April

MATH221 Statistics for Decision Making

Week 7 Homework  

Question 1Two variables have a negative non-linear correlation. Does the dependent variable increase or decrease as the independent variable increases?

  Dependent variable decreases

  Dependent variable increases

  Cannot determine from information given

  Dependent variable would remain the same

Question 2What does the variable ρ represent?

  The critical value for the correlation coefficient

  The coefficient of determination

  The sample correlation coefficient

  The population correlation coefficient

Question 3A baseball player wants to determine if the type of bat he uses each year can be used to predict the amount of improvement in his game. Which variable would be the response variable?

  The improvement in his game

  The number of times he bats

  The type of bat

  The baseball player

Question 4Two variables have a negative linear correlation. Where would the y-intercept of the regression line be located on the y-axis?

  To the right of 0

  To the left of 0

  Cannot determine

  Below 0

Question 5A value of the dependent variable that corresponds to the value of xi would be given the notation of:

  b

  yi

  m

  y1

Question 6What would be the notation for an estimate of y for a specific value of x?

  y?

  b

  yi

  ?

Question 7Which of the following graphs displays the regression equation ?=-0.91x + 11.97

  Scatter plot generally from lower left to upper right where y-intercept is estimated to be around 6

  Scatter plot generally from upper left to lower right where y-intercept is estimated to be around 7

  Scatter plot generally from lower left to upper right where y-intercept is estimated to be around 30

  Scatter plot generally from upper left to lower right where y-intercept is estimated to be around 12

Question 8Find the regression equation for the following data set

x              123         146         127         161         122         174         134         155

y              80          51          59          41          44          59          51          63

  0.13x – 74.50

  -0.13x+74.50

  74.50x – 0.13

  cannot be determined

Question 9A data set whose original x values ranged from 41 through 78 was used to generate a regression equation of ?=5.3x – 21.9. Use the regression equation to predict the value of y when x=70.

  402.1

  Meaningless result

  392.9

  349.1

Question 10A data set whose original x values ranged from 120 through 351 was used to generate a regression equation of ?=0.06x + 14.2. Use the regression equation to predict the value of y when x=110.

  20.80

  Meaningless result

  -7.6

  21.34