Final answer:
To have correlation with 95% confidence, we need to compare the computed correlation coefficient to the critical value from the table of critical values. If the computed value is greater than the critical value, there is a significant linear relationship.
Step-by-step explanation:
The critical value for correlation at a 95% confidence level (5% significance) can be found using the table of critical values. The table provides critical values for different degrees of freedom. To find the critical value, first find the degrees of freedom, which is equal to the sample size minus 2. Then, locate the corresponding critical value on the table. If the computed correlation coefficient is greater than the critical value, then there is a significant linear relationship. If it is less than the critical value, there is not enough evidence to conclude a significant linear relationship.
In the provided example, the computed correlation coefficient is 0.801 with 10 data points, resulting in 8 degrees of freedom. Using Table 12.9, the critical value is 0.632. Since 0.801 is greater than 0.632, the correlation is significant and the regression line can be used for prediction.