Determine whether a correlation exists at α=0.01.

1 answer

To determine whether a correlation exists between two variables at a significance level of \( \alpha = 0.01 \), you'll typically follow these steps:

  1. State the Hypotheses:

    • Null Hypothesis (\( H_0 \)): There is no correlation between the two variables (e.g., \( \rho = 0 \)).
    • Alternative Hypothesis (\( H_a \)): There is a correlation between the two variables (e.g., \( \rho \neq 0 \)).
  2. Collect Data: Collect paired data observations for the two variables you are examining.

  3. Calculate the Correlation Coefficient: Use Pearson's correlation coefficient formula to compute \( r \).

  4. Determine the Critical Value: Use a correlation significance table or a calculator to find the critical values for \( \alpha = 0.01 \) based on your sample size. The critical value can be found for \( n - 2 \) degrees of freedom, where \( n \) is the number of pairs.

  5. Calculate the Test Statistic:

    • Convert the correlation coefficient \( r \) into a test statistic using the formula: \[ t = \frac{r \sqrt{n - 2}}{\sqrt{1 - r^2}} \] where \( n \) is the sample size.
  6. Compare the Test Statistic to Critical Values:

    • If the absolute value of the calculated \( t \) is greater than the critical value from the t-distribution, you reject the null hypothesis.
  7. Draw a Conclusion:

    • If you reject \( H_0 \), it suggests that there is a significant correlation between the variables. Otherwise, you do not have enough evidence to suggest a correlation exists.

If you have specific data, I can help you through each step with actual calculations. Please provide the data or the correlation coefficient and sample size, if available.