Question

The USStates dataset includes the variables HouseholdIncome, the mean household income
for a state (in thousands of dollars), and College, the percentage of a state’s population age 25 or
older who graduated from college. You are going to use this data to investigate the relationship
between College and HouseholdIncome; read through all of the parts of this question to get
your bearings before you do anything!
(a) Use StatKey to create a scatterplot of College versus HouseholdIncome. Describe the trend
shown and determine the correlation between these two variables.
(b) What is the regression equation for predicting College from HouseholdIncome?
(c) What does the slope of this equation tell you? Interpret it in context.
(d) What does the intercept of this equation tell you? Interpret it in context.
(e) If the average household incomes for two states differ by $10,000, how do their college
graduation percentages differ, on average?
(f) For a state with a mean household income of $50,000, what is the predicted percentage of
adults over 25 who have graduated from college?

Answer 1

(a) The scatterplot is:

There is an upward trend in the data and the correlation between these two variables is 0.686.

(b) The regression equation for predicting College from HouseholdIncome is:

y = 0.480 x + 5.277

(c) For every additional household income, the percentage of adults over 25 who have graduated from college will increase by 0.480.

(d) When household income is constant, the percentage of adults over 25 who have graduated from college will increase by 5.277.

(e) Difference = 0.480*10000 = 4800

(f) College = 0.480*50 + 5.277 = 29.26

Please give me a thumbs-up if this helps you out. Thank you!