In: Statistics and Probability
An agent for a residential real estate company in a large city has the business objective of developing more accurate estimates of the monthly rental cost for apartments. Toward that goal, the agent would like to use the size of an apartment, as defined by square footage to predict the monthly rental cost. The agent selects a sample of 25 apartments in a particular residential neighborhood and collects the following data:
Size (square feet) Rent ($)
850, 1950
1450, 2600
1085, 2200
1232, 2500
718, 1950
1485, 2700
1136, 2650
726, 1935
700, 1875
956, 2150
1100, 2400
1285, 2650
1985, 3300
1369, 2800
1175, 2400
1225, 2450
1245, 2100
1259, 2700
1150, 2200
896, 2150
1361, 2600
1040, 2650
755, 2200
1000, 1800
1200, 2750
(a) Construct a scatter plot.
(b) Use the least-squares method to determine the regression coefficients (intercept and slope).
(c) Interpret the meaning of the intercept and slope in this problem.
(d) Predict the monthly rent for an apartment that has 1000 square feet.
(e) Why would it not be appropriate to use the model to predict the monthly rent for apartments that have 500 square feet?
(f) Determine the coefficient of determination , r^2, and interpret its meaning.
(g) Determine the standard error of estimate.(syx)
(h) How useful do you think this regression model is for predicting the monthly rent?
(i) Can you think of other variables that might explain the variation in the monthly rent?
ONLY ANSWER THIS QUESTION IF YOU CAN ANSWER IT COMPLETELY A THROUGH I AND LABEL YOUR ANSWERS!!!
Answer:
a)
b)
c)
y = 1177.12 + 1.065 * x
Interpretation:
Intercept: 1177.12
Intercept is the expected mean value of Y when X = 0 i.e., if x = 0, then predicted value is equal to the intercept
Slope: 1.065
If the value of x is increased by 1 unit then the predicted value will increase by 1.065 units
d)
for, x = 1000 square feet,
Predicted monthly rent = 1177.12 + 1.065 * 1000 = $2242.12