Math Problem Statement

Listed below are the overhead widths​ (in cm) of seals measured from photographs and the weights​ (in kg) of the seals. Construct a​ scatterplot, find the value of the linear correlation coefficient​ r, and find the critical values of r using alphaαequals= 0.01. Is there sufficient evidence to conclude that there is a linear correlation between overhead widths of seals from photographs and the weights of the​ seals?

Overhead Width Weight 7.1 112 7.5 161 9.9 251 9.3 200 8.7 199 8.4 191

Critical Values for the Correlation Coefficient n alpha = .05 alpha = .01 4 0.95 0.99 5 0.878 0.959 6 0.811 0.917 7 0.754 0.875 8 0.707 0.834 9 0.666 0.798 10 0.632 0.765 11 0.602 0.735 12 0.576 0.708 13 0.553 0.684 14 0.532 0.661 15 0.514 0.641 16 0.497 0.623 17 0.482 0.606 18 0.468 0.59 19 0.456 0.575 20 0.444 0.561 25 0.396 0.505 30 0.361 0.463 35 0.335 0.43 40 0.312 0.402 45 0.294 0.378 50 0.279 0.361 60 0.254 0.33 70 0.236 0.305 80 0.22 0.286 90 0.207 0.269 100 0.196 0.256 Note: To test H subscript 0: rho equals 0 against H subscript 1: rho not equal to 0, reject H subscript 0 if the absolute value of r is greater than the critical value in the table.

The linear correlation coefficient is requals=enter your response here. ​(Round to three decimal places as​ needed.)

Solution

import numpy as np import matplotlib.pyplot as plt from scipy.stats import pearsonr

Data

overhead_width = np.array([7.1, 7.5, 9.9, 9.3, 8.7, 8.4]) weights = np.array([112, 161, 251, 200, 199, 191])

Scatterplot

plt.figure(figsize=(8, 6)) plt.scatter(overhead_width, weights, color='blue', edgecolor='black') plt.title('Scatterplot of Overhead Width vs Weight') plt.xlabel('Overhead Width (cm)') plt.ylabel('Weight (kg)') plt.grid(True) plt.show()

Correlation coefficient

r, _ = pearsonr(overhead_width, weights)

Critical value for alpha = 0.01 and n=6

n = len(overhead_width) critical_values = {4: 0.99, 5: 0.959, 6: 0.917, 7: 0.875} critical_value = critical_values[n]

r, critical_value/tmp/ipykernel_12/4001100189.py:11: UserWarning: You passed a edgecolor/edgecolors ('black') for an unfilled marker ('x'). Matplotlib is ignoring the edgecolor in favor of the facecolor. This behavior may change in the future. plt.scatter(overhead_width, weights, color='blue', edgecolor='black')

<<ImageDisplayed>>(0.9499211878781388, 0.917)(0.9499211878781388, 0.917)successThe calculated linear correlation coefficient rr is approximately 0.950 (rounded to three decimal places).

The critical value of rr for n=6n = 6 and α=0.01\alpha = 0.01 is 0.917. Since r=0.950|r| = 0.950 is greater than the critical value of 0.917, there is sufficient evidence to reject the null hypothesis H0:ρ=0H_0: \rho = 0.

Conclusion:

There is significant evidence to conclude that there is a linear correlation between the overhead widths of seals and their weights.

Would you like me to assist further with interpretation, or do you have questions about this process?

Here are 5 related questions:

  1. What does the correlation coefficient rr indicate about the relationship between width and weight?
  2. How would the critical value change if the sample size were larger?
  3. What are the assumptions of the Pearson correlation test?
  4. Can we use this correlation for prediction? Why or why not?
  5. How would outliers affect the correlation coefficient in this scenario?

Tip: A correlation does not imply causation; always examine the context of the data!

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Math Problem Analysis

Mathematical Concepts

Statistics
Linear Correlation
Hypothesis Testing

Formulas

Pearson correlation coefficient formula: r = Σ((xi - x̄)(yi - ȳ)) / sqrt(Σ(xi - x̄)²Σ(yi - ȳ)²)
Critical value comparison for hypothesis testing

Theorems

Pearson Correlation Theorem

Suitable Grade Level

Grades 10-12