Question

Following is the average amount of money left to children by the tooth fairy in recent years, according to a  

poll of parents.  The table compares these payout amounts to the U.S. unemployment rate at the same

time.  The scatterplot for the data is also given.           

Unemployment Rate (%)	Average Amount Left
4.0	$4.13
4.5	4.66
5.0	3.91
5.4	4.36
6.7	3.50
7.5	2.42
8.2	2.10

                        

            a)  Find the value of the linear correlation coefficient .

            b)  Is there sufficient evidence to support the claim that there is a significant linear correlation between

                 the unemployment rate and the average amount left by the tooth fairy?  What do you base your conclusion on?

                                              

c)  Specify the value of the coefficient of determination .  Give a written interpretation of this value.

d)  Find the equation of the least-squares regression line.

e)  Confirm that you have examined the scatterplot with the regression line from Statdisk:

f)  What is the value of the slope of the regression equation?  Give a written interpretation of the slope in the context of this problem.

g)  What is the value of the y-intercept of the regression equation?  Give a written interpretation of the y-intercept in the context of this problem.

h)  What is the best predicted average tooth fairy payout for a year with a 4.5% unemployment rate?

Answer 1