Question

oot ulcers are a common problem for people with diabetes. Higher skin temperatures on the foot indicate an increased risk of ulcers. In a study performed at the Colorado School of Mines, skin temperatures on both feet were measured, in degrees Fahrenheit, for 8 diabetic patients.
Left foot
78
89
80
87
88
85
89
76
Right Foot
78
87
80
82
89
85
90
81

The regression line is y=24.5+0.7083x

If the left foot temperatures of two patients differ by 3 degrees, by how much would you predict their right foot temperatures to differ? Round the answer to three decimal places.

Answers

GPT-4o mini
To find out how much the right foot temperatures would differ based on a 3-degree difference in left foot temperatures, we can use the slope of the regression line.

The regression line given is:
\[ y = 24.5 + 0.7083x \]
where \( y \) is the predicted right foot temperature and \( x \) is the left foot temperature.

The slope \( 0.7083 \) indicates how much the right foot temperature changes for each 1-degree change in left foot temperature.

Given that the left foot temperatures of two patients differ by 3 degrees, we can calculate the predicted difference in the right foot temperatures (denoted as \( \Delta y \)) as follows:

\[
\Delta y = 0.7083 \times \Delta x
\]
where \( \Delta x = 3 \) degrees.

Now substituting the value:

\[
\Delta y = 0.7083 \times 3 = 2.1249
\]

Now we’ll round the result to three decimal places:

\[
\Delta y \approx 2.125
\]

Thus, if the left foot temperatures of two patients differ by 3 degrees, we would predict their right foot temperatures to differ by approximately **2.125 degrees**.
Predict the right foot temperature for a patient whose left foot temperature is 86 degrees. Round the answer to one decimal place.
GPT-4o mini
To predict the right foot temperature for a patient whose left foot temperature is 86 degrees, we will use the regression line equation:

\[
y = 24.5 + 0.7083x
\]

where \( x \) is the left foot temperature. In this case, \( x = 86 \).

Now, substituting the value of \( x \) into the equation:

\[
y = 24.5 + 0.7083 \times 86
\]

First, calculate the multiplication:

\[
0.7083 \times 86 = 60.918
\]

Now, add this to 24.5:

\[
y = 24.5 + 60.918 = 85.418
\]

Now we round the answer to one decimal place:

\[
y \approx 85.4
\]

Thus, the predicted right foot temperature for a patient whose left foot temperature is 86 degrees is approximately **85.4 degrees**.