Devry MATH221 Statistics for Decision Making Week 7 Homework
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