Below are the average heights for American boys. (Source: Physician's Handbook, 1990)
a. Decide which variable should be the independent variable and which should be the dependent variable.
b. Make a scatter plot of the data.
c. Does it appear from inspection that there is a relationship between the variables? Why or why not?
d. Calculate the least squares line. Put the equation in the form of: y = a + bx
e. Find the correlation coefficient. Is it significant?
f. Find the estimated average height for a one year-old. Find the estimated average height for an eleven year-old.
g. Use the two points in (f) to plot the least squares line on your graph from (b).
h. Does it appear that a line is the best way to fit the data? Why or why not?
i. Are there any outliers in the above data?
j. Use the least squares line to estimate the average height for a sixty-two year-old man. Do you think that your answer is reasonable? Why or why not?
k. What is the slope of the least squares (best-fit) line? Interpret the slope.