Question 1

If cov(x,y)= 20, $s _ { x } ^ { 2 } = 16$ and $s _ { y } ^ { 2 } = 49$ then the sample coefficient of correlation r is:

Accepted Answer

A)  1.400 
B)  0.026 
C)  0.714 
D)  None of these choices. 
A)  1.400 
B)  0.026 
C)  0.714 
D)  None of these choices.

Question 2

The strength of the linear relationship between two interval variables can be measured by the:

Accepted Answer

A)  coefficient of variation. 
B)  coefficient of correlation. 
C)  slope of the regression line. 
D)  Y-intercept. 
A)  coefficient of variation. 
B)  coefficient of correlation. 
C)  slope of the regression line. 
D)  Y-intercept.

Question 3

If the standard deviation of x is 18,the covariance of x and y is 120,the coefficient r = 0.90,then the standard deviation of y is 54.87.

Accepted Answer

A) True 
 B)False

Question 4

The variance is a measure of the linear relationship between two variables.

Accepted Answer

A) True 
 B)False

Question 5

The magnitude of the correlation measures the ____________________ of a linear relationship.

Accepted Answer

The answer of The magnitude of the correlation measures the...

Question 6

A perfect straight line sloping downward would produce a correlation coefficient equal to:

Accepted Answer

A)  +1.0 
B)  -1.0 
C)  0.0 
D)  Cannot tell from the information given. 
A)  +1.0 
B)  -1.0 
C)  0.0 
D)  Cannot tell from the information given.

Question 7

The Y-intercept,b0,of the least squares line $\hat { y } = b _ { 0 } + b _ { 1 } x$ represents the:

Accepted Answer

A)  estimated average value of Y when X = 0. 
B)  estimated average change in Y per unit change in X. 
C)  predicted value of Y. 
D)  variation around the sample regression line. 
A)  estimated average value of Y when X = 0. 
B)  estimated average change in Y per unit change in X. 
C)  predicted value of Y. 
D)  variation around the sample regression line.

Question 8

Which of the following is a property of the slope,b1?

Accepted Answer

A)  The slope equals one if X and Y have the same variance. 
B)  The slope has the same sign as r,the coefficient of correlation. 
C)  The slope equals one if r equals one. 
D)  All of these choices are true. 
A)  The slope equals one if X and Y have the same variance. 
B)  The slope has the same sign as r,the coefficient of correlation. 
C)  The slope equals one if r equals one. 
D)  All of these choices are true.

Question 9

The slope b1 of the least squares line $\hat { y } = b _ { 0 } + b _ { 1 } x$ represents the:

Accepted Answer

A)  predicted value of Y when X = 0. 
B)  estimated average change in Y per unit change in X. 
C)  predicted value of Y. 
D)  variation around the regression line. 
A)  predicted value of Y when X = 0. 
B)  estimated average change in Y per unit change in X. 
C)  predicted value of Y. 
D)  variation around the regression line.

Question 10

The denominator in the calculation of the sample covariance,cov (x,y),is:

Accepted Answer

A)  n -2 
B)  n - 1 
C)  n 
D)  2n - 1 
A)  n -2 
B)  n - 1 
C)  n 
D)  2n - 1

Question 11

If the coefficient of correlation r = -.81,the standard deviations of x and y are 20 and 25,respectively,then cov(x,y)must be -405.0.

Accepted Answer

A) True 
 B)False

Question 12

The ____________________ of the correlation indicates the direction of a linear relationship.

Accepted Answer

The answer of The ____________________ of the correlation indicates the...

Question 13

If the coefficient of correlation r = 0,then there can be no linear relationship between the dependent variable y and the independent variable x.

Accepted Answer

A) True 
 B)False

Question 14

If $\sum x _ { i } = 7587$ , $\sum y _ { i } = 7106.4$ ,n = 12,and the slope equals 0.5,then the y-intercept of the least squares line is b0 = 276.08.

Accepted Answer

A) True 
 B)False

Question 15

If the correlation coefficient r = 1.00,then all the observations must fall exactly on:

Accepted Answer

A)  a straight line with a slope that equals 1.00. 
B)  a straight line with a negative slope. 
C)  a straight line with a positive slope. 
D)  a horizontal straight line with a zero slope. 
A)  a straight line with a slope that equals 1.00. 
B)  a straight line with a negative slope. 
C)  a straight line with a positive slope. 
D)  a horizontal straight line with a zero slope.

Question 16

The coefficient of determination is the percentage of variation in the ____________________ variable that is explained by the variation in the ____________________ variable.

Accepted Answer

dependent;

Question 17

The advantage that the coefficient of correlation has over the covariance is that the former has a set lower and upper limit.

Accepted Answer

A) True 
 B)False

Question 18

The y-intercept of the least squares line is the point on the line when ________________ = 0.

Accepted Answer

The answer of The y-intercept of the least squares line...

Question 19

Three measures of the linear relationship between x and y are the coefficient of correlation,the coefficient of determination,and the coefficient of variation.

Accepted Answer

A) True 
 B)False

Exam 4: B: Numerical Descriptive Techniques

If cov(x,y)= 20, sx2=16s _ { x } ^ { 2 } = 16sx2​=16 and sy2=49s _ { y } ^ { 2 } = 49sy2​=49 then the sample coefficient of correlation r is:

The strength of the linear relationship between two interval variables can be measured by the:

If the standard deviation of x is 18,the covariance of x and y is 120,the coefficient r = 0.90,then the standard deviation of y is 54.87.

The variance is a measure of the linear relationship between two variables.

The magnitude of the correlation measures the ____________________ of a linear relationship.

A perfect straight line sloping downward would produce a correlation coefficient equal to:

The Y-intercept,b0,of the least squares line y^=b0+b1x\hat { y } = b _ { 0 } + b _ { 1 } xy^​=b0​+b1​x represents the:

Which of the following is a property of the slope,b1?

The slope b1 of the least squares line y^=b0+b1x\hat { y } = b _ { 0 } + b _ { 1 } xy^​=b0​+b1​x represents the:

The denominator in the calculation of the sample covariance,cov (x,y),is:

If the coefficient of correlation r = -.81,the standard deviations of x and y are 20 and 25,respectively,then cov(x,y)must be -405.0.

The ____________________ of the correlation indicates the direction of a linear relationship.

If the coefficient of correlation r = 0,then there can be no linear relationship between the dependent variable y and the independent variable x.

If ∑xi=7587\sum x _ { i } = 7587∑xi​=7587 , ∑yi=7106.4\sum y _ { i } = 7106.4∑yi​=7106.4 ,n = 12,and the slope equals 0.5,then the y-intercept of the least squares line is b0 = 276.08.

If the correlation coefficient r = 1.00,then all the observations must fall exactly on:

The coefficient of determination is the percentage of variation in the ____________________ variable that is explained by the variation in the ____________________ variable.

The advantage that the coefficient of correlation has over the covariance is that the former has a set lower and upper limit.

The y-intercept of the least squares line is the point on the line when ________________ = 0.

Three measures of the linear relationship between x and y are the coefficient of correlation,the coefficient of determination,and the coefficient of variation.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

A: Numerical Descriptive Techniques

C: Numerical Descriptive Techniques

Data Collection and Sampling

Probability

A: Random Variables and Discrete Probability Distributions

B: Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

A: Simple Linear Regression and Correlation

B: Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Time-Series Analysis and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

If cov(x,y)= 20, $s _ { x } ^ { 2 } = 16$ and $s _ { y } ^ { 2 } = 49$ then the sample coefficient of correlation r is:

The Y-intercept,b₀,of the least squares line $\hat { y } = b _ { 0 } + b _ { 1 } x$ represents the:

Which of the following is a property of the slope,b₁?

The slope b₁ of the least squares line $\hat { y } = b _ { 0 } + b _ { 1 } x$ represents the:

If $\sum x _ { i } = 7587$ , $\sum y _ { i } = 7106.4$ ,n = 12,and the slope equals 0.5,then the y-intercept of the least squares line is b₀ = 276.08.

The coefficient of determination is the percentage of variation in the variable that is explained by the variation in the variable.