1.    The strength of the linear relationship between two numerical variables may be measured by the

[removed]		scatter diagram.
[removed]		coefficient of correlation.
[removed]		slope.
[removed]		Y-intercept.

10 points  

Question 2

1.      

If you wanted to analyze the correlation between the NUMBER OF HOURS PRACTICED and the NUMBER OF TARGETS HIT by a sharpshooter, which variable would be the dependent variable?

[removed]		Number of hours practiced
[removed]		Number of targets hit
[removed]		Neither one is dependent
[removed]		Either one could be dependent (impossible to determine)

10 points  

Question 3

1.      

Before proceeding with a simple linear regression, you should first construct a scatter diagram in order that you can remove all outliers from the data.
 

[removed]True

[removed]False

10 points  

Question 4

1.      

What does it mean to have a negative coefficient in the regression model?

[removed]		That variable reduces the coefficient of determination.
[removed]		The values for that variable are negative.
[removed]		There is an inverse relationship with that variable.
[removed]		The correlation is weak.

10 points  

Question 5

1.      

Assuming a linear relationship between X and Y, if the coefficient of correlation (r) equals -0.30,

[removed]		there is no correlation.
[removed]		the slope (b1) is negative.
[removed]		variable X is larger than variable Y.
[removed]		the variance of X is negative.

10 points  

Question 6

1.      

If the hypothesis test for correlation is found to be significant (i.e., we rejected the null hypothesis / accepted the alternate hypothesis), what can we automatically conclude about the strength of the correlation?

[removed]		We can conclude that the correlation must be strong.
[removed]		We can only conclude that the correlation is not weak
[removed]		We cannot conclude anything about the strength of the correlation yet.

10 points  

Question 7

1.      

A negative correlation coefficient implies that as the value of independent variable increases, the value of the dependent variable _________________.
 

[removed]		Increases
[removed]		Decreases
[removed]		Cannot be determined from the information given

10 points  

Question 8

1.      

There is a strong positive correlation between a baby’s weight and the size of his/her vocabulary. From this we can conclude that overeating will improve one’s vocabulary.
 

[removed]True

[removed]False

10 points  

Question 9

1.      

If the correlation coefficient (r) = 1.00, then

[removed]		all the data points must fall exactly on a straight line with a slope that equals 1.00.
[removed]		all the data points must fall exactly on a straight line with a negative slope.
[removed]		all the data points must fall exactly on a straight line with a positive slope.
[removed]		all the data points must fall exactly on a horizontal straight line with a zero slope.

10 points  

Question 10

1.      

Assume the regression model for predicting home prices by the square footage were: PRICE = 12510 + 83 (SQRFT) For every additional one square foot, how much does the price increase?

[removed]		$12,593
[removed]		$83
[removed]		$166
[removed]		Cannot be determined from the information given.

 

In a metal fabrication process, metal rods are produced to a specified target length of 15 feet. Suppose that the lengths are normally distributed. A quality control specialist collects a random sample of 16 rods and finds the sample mean length to be 14.8 feet and a standard deviation of 0.65 feet. The standard error of the mean is 

A 0.65 ft.
B 0.1625 ft.
C 0.0098 ft.
D 0.346 ft.
E 1.625 ft.

EU (European Union) countries report that 46% of their labor force is female. The United Nations wants to determine if the percentage of females in the U.S. labor force is the same. Based on a sample of 500 employment records, representatives from the United States Department of Labor find that the 95% confidence interval for the proportion of females in the U.S. labor force is 0.357 to 0.443. Which of the following is the correct interpretation? 

A We are 95% confident that between 35.7% and 44.3% of the persons in the U.S. labor force is female
B The margin of error for the true percentage of females in the U.S. labor force is between 35.7% and 44.3%
C The percentage of females in the U.S. labor force is between 35.7% and 44.3%
D All samples of size 500 will yield a percentage of females in the U.S. labor force that falls within 35.7% and 44.3%
E None of these

In a metal fabrication process, metal rods are produced to a specified target length of 15 feet. Suppose that the lengths are normally distributed. A quality control specialist collects a random sample of 16 rods and finds the sample mean length to be 14.8 feet and a standard deviation of 0.65 feet. Which of the following statements is true? 

A The sampling distribution for the sample mean follows the t-distribution with 15 degrees of freedom
B The mean of the sampling distribution for the sample mean is 14.8 feet
C The standard error is 0.65 feet
D The sampling distribution for the sample mean follows the t-distribution with 16 degrees of freedom
E The sampling distribution for the sample mean is Normal with a mean of 14.8 feet and standard deviation of 0.65 feet