r and r^2
Interpretations
LSRL
Random Cory Trivia
Mixed Bag
100
Determine the correlation coefficient for the following:
r = 0.993
100
Interpret r = -0.23
The relationship between x and y is weak and negative.
100
What does the abbreviation LSRL stand for?
Least Squares Regression Line
100
How many cats does Cory have?
2
100
A data point is known to be (5, 67). The LSRL gives a
haty=0+20x
What is the value of the residual?
Residual = -33
200
Determine the coefficient of determination if r = -0.96
0.9216
200
Interpret a slope of 9.231.
The y changes by 9.231 when x changes by one.
200
Calculate the y-intercept (predict heartrate) for the following data set:
48.068
200
How old was Cory when he moved to Florida?
14
200
True/False
A negative residual means the data point falls below the regression line.
True!
300
True/False
R^2 is always positive
True
300
Interpret a y-intercept of 87.222
The y-value is 87.222 when x is zero.
300
Calculate the slope (predict heart rate) for the following data set:
0.511
300
To what country is Cory traveling for Thanksgiving?
Ireland
300
What is the sum of the residuals for a LSRL?
Zero
400
The correlation coefficient between an explanatory and response variable is r = -0.234. If you were switch the explanatory and response variable, what would the new correlation coefficient be?
r = -0.234
400
Interpret r2 = 0.247
24.7% of the variability in y is explained by the LSRL.
400
Given a set of ordered pairs (x,y) with sx = 2.5, sy = 1.9, r = .63 , what is the slope of the regression line of y on x?
0.4788
400
In what city did Cory live before moving to Maryland?
Tallahassee
400
Which are true?
I. Random scatter in the residuals indicates a linear model.
II. If two variables are very strongly associated, then the correlation between them will be near +1.0 or −1.0.
III. Changing the units of measurement for x or y changes the correlation coefficient.
I and II
500
The relationship between the number of hours studied for a AP Statistics test and the score on the test is r = 0.371. If you were to measure the time studied in minutes (instead of hours) what would the new correlation coefficient be?
r = 0.371
500
Interpret the following residual plot:
The data is not linear because the residual plot has a pattern.
500
Which of the following will be negative if the relationship between x and y is negative?
I. y-intercept
II. Correlation Coefficient
III. Coefficient of Determination
IV. Slope
I and IV
500
In what state was Cory born?
Delaware
500
With regard to regression, which of the following statements about outliers are true?
I. Outliers have large residuals.
II.Outliers have small residuals.
III. Removal of an outlier affects the regression line in a meaningful way.
I and III