Math Problem Statement

Annual high temperatures in a certain location have been tracked for 8 years. Calculate the correlation coefficient and test its significance at a 0.01 significance level.

Solution

Let's walk through this step by step:

  1. Calculate the correlation coefficient rr: The formula for the Pearson correlation coefficient rr is: [ r = \frac{n(\sum xy) - (\sum x)(\sum y)}{\sqrt{[n \sum x^2 - (\sum x)^2][n \sum y^2 - (\sum y)^2]}} ] We will need to calculate the necessary sums:

    • x\sum x, y\sum y
    • x2\sum x^2, y2\sum y^2
    • xy\sum xy
  2. Test statistic: To test the significance of the correlation coefficient, we use the formula for the test statistic tt: t=rn21r2t = \frac{r \sqrt{n-2}}{\sqrt{1 - r^2}} where nn is the number of data points, and rr is the correlation coefficient calculated earlier.

  3. P-value: Using the test statistic tt, we can calculate the p-value by referring to the t-distribution table with n2n-2 degrees of freedom.

  4. Decision: Based on the p-value, if it is less than the significance level α=0.01\alpha = 0.01, we reject the null hypothesis H0H_0, otherwise we fail to reject it.

Now, let's calculate these values step by step.


Data given:

  • x={3,4,5,6,7,8,9,10}x = \{3, 4, 5, 6, 7, 8, 9, 10\}
  • y={7.4,11.5,13.2,16.6,17.2,18.4,20.2,20.9}y = \{7.4, 11.5, 13.2, 16.6, 17.2, 18.4, 20.2, 20.9\}

I'll start calculating the necessary sums.The calculated correlation coefficient rr is 0.970 (rounded to three decimal places).

Now, let's move on to calculating the test statistic using the formula: t=rn21r2t = \frac{r \sqrt{n-2}}{\sqrt{1 - r^2}} where n=8n = 8 and r=0.970r = 0.970.

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Math Problem Analysis

Mathematical Concepts

Statistics
Correlation
Hypothesis Testing

Formulas

Pearson correlation coefficient formula: r = [n(∑xy) - (∑x)(∑y)] / sqrt{[n∑x^2 - (∑x)^2][n∑y^2 - (∑y)^2]}
Test statistic for correlation: t = r * sqrt(n - 2) / sqrt(1 - r^2)

Theorems

t-distribution
Hypothesis testing

Suitable Grade Level

College-level Statistics or Advanced High School