Math Problem Statement

Shown below is the output from a linear model predicting armspan​ (in cm) from height

left parenthesis in inches right parenthesis(in inches)

and summary statistics. Assume that the association between armspan and height is linear. Use the output and summary statistics to complete parts a through d.

LinReg

yequals=aplus+bx

aequals=17.6567055317.65670553

bequals=2.2259475222.225947522

r squaredr2equals=0.8450473460.845047346

requals=0.9192645680.919264568

Mean

Standard Deviation

​Height, x

63.6863.68

3.303.30

​Armspan, y

159.41159.41

8.008.00

Question content area bottom

Part 1

a. Report the regression​ equation, using the words​ "Height" and​ "Armspan," not x and y.

A.

Predicted

Armspanequals=2.232.23plus+17.6617.66

Height

B.

Predicted

Armspanequals=17.6617.66plus+2.232.23

Height

Your answer is correct.

C.

Predicted

Heightequals=2.232.23plus+17.6617.66

Armspan

D.

Predicted

Heightequals=17.6617.66plus+2.232.23

Armspan

Part 2

b. Determine the corresponding values and verify the slope by using the formula

bequals=r StartFraction s Subscript y Over s Subscript x EndFractionrsysx.

requals=

enter your response here

​(Round to three decimal places as​ needed.)

s Subscript y Baseline equalssy=

enter your response here

​(Round to two decimal places as​ needed.)

s Subscript x Baseline equalssx=

enter your response here

​(Round to two decimal places as​ needed.)

bequals=

enter your response here

​(Round to two decimal places as​ needed.)

Solution

Part 1

a. Report the regression equation, using the words "Height" and "Armspan," not x and y.

From the linear regression equation format y=a+bxy = a + bx, where:

  • a=17.66a = 17.66 is the y-intercept,
  • b=2.23b = 2.23 is the slope of the regression line,
  • The equation can be written as:

Predicted Armspan = 17.66 + 2.23 * Height

Correct answer:

  • B. Predicted Armspan = 17.66 + 2.23 * Height

Part 2

b. Determine the corresponding values and verify the slope by using the formula:

b=rsysxb = r \cdot \frac{s_y}{s_x}

Where:

  • rr is the correlation coefficient,
  • sys_y is the standard deviation of Armspan,
  • sxs_x is the standard deviation of Height.

From the given data:

  • r=0.919r = 0.919 (correlation coefficient),
  • sy=8.00s_y = 8.00 (standard deviation of Armspan),
  • sx=3.30s_x = 3.30 (standard deviation of Height).

Using the formula:

b=0.9198.003.30b = 0.919 \cdot \frac{8.00}{3.30}

Now, let's compute the value for bb.

b=0.9192.42422.23b = 0.919 \cdot 2.4242 \approx 2.23

Thus, the slope bb is approximately 2.23.


Summary of the values:

  • r = 0.919 (round to three decimal places)
  • sy=8.00s_y = 8.00 (round to two decimal places)
  • sx=3.30s_x = 3.30 (round to two decimal places)
  • b = 2.23 (round to two decimal places)

Let me know if you'd like further details or have any other questions!


Related Questions:

  1. How would the regression equation change if the standard deviation of Armspan were larger or smaller?
  2. What does the correlation coefficient r=0.919r = 0.919 tell us about the relationship between Height and Armspan?
  3. How do you interpret the y-intercept (17.66) in the context of this regression model?
  4. How does increasing the sample size impact the accuracy of the regression model?
  5. How can the standard deviations of Height and Armspan affect the slope of the regression line?

Tip: A higher correlation coefficient (closer to 1 or -1) generally means a stronger linear relationship between the two variables.

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Correlation
Standard Deviation
Regression Equation

Formulas

Regression equation: y = a + bx
Slope formula: b = r * (sy / sx)

Theorems

Least Squares Regression

Suitable Grade Level

Grades 10-12