Math Problem Statement

Listed below are foot lengths (mm) and heights (mm) of males. Find the regression equation, letting foot length be the predictor (x) variable. Find the best predicted height of a male with a foot length of 272.8 mm. How does the result compare to the actual height of 1776 mm? Use a significance level of 0.05.

Solution

PIL import Image import pytesseract

Load the uploaded image to extract text

image_path = "/mnt/data/1733371492956wspg1f4a.jpg" extracted_text = pytesseract.image_to_string(Image.open(image_path))

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Steps to Solve:

  1. Use the provided foot length and height data.
  2. Calculate the regression equation (find slope b1b_1 and intercept b0b_0).
  3. Predict the height for a foot length of 272.8 mm.
  4. Compare the predicted height to the actual height of 1776 mm.

Let me calculate these steps. numpy as np import pandas as pd

Data from the table in the image

foot_lengths = np.array([282.2, 278.3, 253.0, 258.6, 279.1, 258.1, 274.1, 262.3]) heights = np.array([1784.8, 1771.2, 1675.6, 1646.3, 1858.9, 1709.8, 1788.8, 1737.0])

Calculate regression coefficients

n = len(foot_lengths) x_mean = np.mean(foot_lengths) y_mean = np.mean(heights)

Calculate slope (b1) and intercept (b0)

b1 = np.sum((foot_lengths - x_mean) * (heights - y_mean)) / np.sum((foot_lengths - x_mean)**2) b0 = y_mean - b1 * x_mean

Predict the height for a foot length of 272.8 mm

predicted_height = b0 + b1 * 272.8

Results

b0, b1, predicted_heightThe regression equation is:

y^=355.92+5.18x\hat{y} = 355.92 + 5.18x

where:

  • y^\hat{y} is the predicted height,
  • xx is the foot length.

For a foot length of 272.8 mm, the predicted height is approximately 1770.34mm1770.34 \, \text{mm}.

Comparison with the actual height:

The actual height is 1776mm1776 \, \text{mm}. The difference between the predicted and actual heights is:

17761770.34=5.66mm.1776 - 1770.34 = 5.66 \, \text{mm}.

Would you like a detailed explanation of the steps, or do you have any specific questions?

Follow-Up Questions:

  1. How is the slope (b1b_1) calculated in a regression analysis?
  2. What does the intercept (b0b_0) represent in the regression equation?
  3. How can we test if the regression equation is statistically significant?
  4. What is the importance of the R2R^2 value in regression analysis?
  5. How would using a different significance level (α\alpha) affect the conclusions?

Tip:

Always check the residuals (differences between actual and predicted values) to evaluate the fit of your regression model.

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Prediction
Statistical Analysis

Formulas

Regression Equation: ŷ = b0 + b1x
Slope (b1): b1 = Σ((x - x̄)(y - ȳ)) / Σ((x - x̄)^2)
Intercept (b0): b0 = ȳ - b1x̄
Predicted Value: ŷ = b0 + b1x

Theorems

Least Squares Regression Line

Suitable Grade Level

College/University