The least squares regression line minimizes the sum of the

Squared differences between actual and predicted Y values

Which of the following statements is true?

The correlation can be strongly affected by outliers

Which of the following statements about correlation r are incorrect?

It is not affected by extreme values

Suppose a study finds that the correlation relating family income to SAT scores is r=1.

There is a strong association between income and SAT scores

Which of the following is incorrect in regards to correlations?

Like the mean & standard deviation, correlation is resistant

The correlation coefficient is

Number between -1 and +1 that measures strength & direction

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Duplicate of Chapter 3: Describing Relationships

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Questions 15

Answers

1
A study is conducted to determine if college academic results can be predicted based on HS GPA
Number of credits the student is taking
Academic performance of the first year student
Grade point average (GPA)
The college
2
The correlation coefficient may assume any value between
0 and 1
0 and 10
-1 and 1
-1 and 0
3
If r= -1, then we can conclude that there is a perfect relationship between X and Y.
True
False
4
The least squares regression line minimizes the sum of the
Absolute deviations between actual and predicted Y values
Squared differences between actual and predicted Y values
Differences between actual and predicted x values
Differences between actual and predicted Y values
5
The strength of the relationship between two quantitative variables can be measure by the:
Slope of the regression equation
Y intercept of the regression equation
Coefficient of correlation
Coefficient of determination
6
Which of the following statements, concerning least squares regression lines (LSRL), is true?
All of the above
The sum of the residuals is always 0
A plot of the residuals is useful for assessing fit of LSRL
residual= observed y- predicted y
7
Match the following scatterplot to the r value below that best describes it
-0.3
-0.99
0
-0.7
8
Which of the following statements is true?
Values of r near 0 indicate a strong linear relationship
Strong correlation refers to a cause and effect relationship
Correlation changes when the x and y variables are reversed
The correlation can be strongly affected by outliers
9
Which of the following statements about correlation r are incorrect?
Correlation r is just a number
It's not affected by which variable is called x or y
It is not affected by extreme values
It is not affected by changes in measurement units
10
The least squares regression line for average tree height based on trunk diameter: Y^=-3.6+4x,
20.1
7.4
24.4
31.6
11
Suppose a study finds that the correlation relating family income to SAT scores is r=1.
There is a strong association between income and SAT scores
Wealth causes high SAT scores
No conclusions can be made
Poverty causes low SAT scores
12
It is found that grades in math and hours of time spent completing homework have an association
Time spent studying and completing homework
Grade in mathematics
Homework
Connection between the variables is not clear
13
Which of the following is incorrect in regards to correlations?
Correlation is not a complete summary of two-variable data
Correlation requires that both variables be quantitative
Correlation does not imply causation
Like the mean & standard deviation, correlation is resistant
14
The correlation coefficient is
Always equal to the slop of the regression line
Number between -1 and +1 that measures strength & direction
Never equal to 0
A positive number that measure only the strength
15
Which of the following best describes the correlation between two variables if r= 0.978?
Negative and strong
Positive and strong
Negative and weak
Positive and weak

Duplicate of Chapter 3: Describing Relationships Flashcards | StudBud