In: Statistics and Probability
One of the biggest factors in determining the value of a home is the square footage. The accompanying data represent the square footage and selling price (in thousands of dollars) for a random sample of homes for sale in a certain region. Complete parts (a) through (h) below.
Square Footage, x |
Selling Price ($000s), y |
||
21162116 |
366.2366.2 |
||
31243124 |
365.1365.1 |
||
11251125 |
189.4189.4 |
||
18771877 |
322.7322.7 |
||
31363136 |
624.2624.2 |
||
27382738 |
364.4364.4 |
||
42614261 |
650.7650.7 |
||
23062306 |
392392 |
||
27052705 |
440440 |
||
17801780 |
309.4309.4 |
||
18181818 |
275.8275.8 |
||
39463946 |
710.3 |
(c) Determine the linear correlation coefficient between square footage and asking price.
requals=nothing
(Round to three decimal places as needed.)
(d) Is there a linear relation between square footage and asking price?
Yes
No
(e) Find the least-squares regression line treating square footage as the explanatory variable.
ModifyingAbove y with caretyequals=nothingxplus+left parenthesis nothing right parenthesis
(Round the slope to three decimal places as needed. Round the intercept to one decimal place as needed.)
(f) Interpret the slope. Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. For a house that is sold for $0, the predicted square footage is .___
(Round to three decimal places as needed.)
B.For every additional thousand dollars in selling price, the square footage
increase by ____ square feet, on average.
(Round to three decimal places as needed.)
C. For a house that is 0 square feet, the predicted selling price is ____ thousand dollars.
(Round to three decimal places as needed.)
D. For every additional square foot, the selling price increase by ___ thousand dollars, on average.
(Round to three decimal places as needed.)
E. It is not appropriate to interpret the slope.
(g) Is it reasonable to interpret the y-intercept? Why? Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. Yes —a house of ____ square feet is possible and within the scope of the model.
(Type an integer or a simplified fraction.)
B.No—a house of _____ square feet is outside the scope of the model
(Type an integer or a simplified fraction.)
C.No —a house of ____ square feet is not possible.
(Type an integer or a simplified fraction.)
D.No—a house of _______square feet is not possible and outside the scope of the model.
(Type an integer or a simplified fraction.)
E. More information about the houses is necessary before deciding.
(h) One home that is 14261426 square feet is sold for $265265 thousand. Is this home's price above or below average for a home of this size?
The home's price is the average price.(Options: 1.Below 2. Average The average price of a home that is 14261426 square feet is ___ thousand.
(Round to the nearest whole number as needed.)
X: Square footage and Y: Selling price
c) Correlation coefficient (r)
Where n = 12 pairs of x and y
(d) The null and alternative hypotheses are:
H0: There is no linear relationship between the two variables
H1: There is a linear relationship between the two variables
r = 0.912
The critical value using the critical value table for correlation coefficient for degrees of freedom n - 2 = 10 and alpha for two tailed as 0.05 is 0.576
Critical value is less than r so reject the null hypothesis.
That is there is linear relation between square footage and asking price.
The answer is Yes
(e) Least square regression line
Where y - price
x - square footage
a - slope and b - intercept
The formula to find the slope
The formula of intercept
The least equare regression equation is
f) Interpretation of slope
It shows the increasde amount in x, if we increase x by 1 then y is increadsed by 0.158
Option D is correct
D. For every additional square foot, the selling price increase by 0.158 thousand dollars, on average.
g) Interpretation of intercept
If we take x as 0 then the price will increase by 9.7
But the house with 0 square footage is not possible, so option C is correct
C. No a house of 0 square feet is not possible.
h) x = 1426 and y = $265
Plug x = 1426 in the least square regression line to find yhat
The home price for 1426 square feet is $235
y - yhat = 265 - 235 = 30
The difference is positive so it is above average.