Math Problem Statement
Solution
We are given that some observations were recorded incorrectly, and the task is to find the correct correlation coefficient between and .
Given Data:
Incorrect observations:
- For and
Correct observations:
- Corrected values are and
Step-by-step process:
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Adjustment to sums due to incorrect observations:
First, calculate the incorrect contributions to the sums from the incorrect values:
-
Correct sums for the correct pairs of observations:
-
Adjust the original sums:
-
Now, use the formula for the correlation coefficient : [ r = \frac{n \Sigma xy - (\Sigma x)(\Sigma y)}{\sqrt{[n \Sigma x^2 - (\Sigma x)^2][n \Sigma y^2 - (\Sigma y)^2]}} ] Plugging in the corrected values: [ r = \frac{25 \times 520 - (125 \times 100)}{\sqrt{[25 \times 650 - (125)^2][25 \times 436 - (100)^2]}} ] Let's compute this step by step.The correct correlation coefficient between and after making the necessary corrections is approximately .
Would you like further clarification on any part of the process or detailed steps on how we reached this result?
Here are some related questions for further understanding:
- How would the correlation coefficient change if the incorrect observations were more extreme?
- What is the significance of the correlation coefficient being positive in this case?
- How can the correlation coefficient be interpreted in real-life situations involving two variables?
- What is the impact of having incorrect observations on the calculation of correlation coefficients?
- Can we determine if the relationship between and is linear or nonlinear from the correlation coefficient alone?
Tip: Always double-check observations and data before performing any statistical analysis, as incorrect entries can significantly affect the results.
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Math Problem Analysis
Mathematical Concepts
Statistics
Correlation Coefficient
Data Correction
Formulas
Sum of x (Σx), Sum of y (Σy), Sum of squares of x (Σx²), Sum of squares of y (Σy²), Sum of products of x and y (Σxy)
Correlation Coefficient: r = [nΣxy - (Σx)(Σy)] / sqrt{[nΣx² - (Σx)²][nΣy² - (Σy)²]}
Theorems
Pearson Correlation Coefficient
Suitable Grade Level
Grades 10-12