What is the critical t-value (found in the t-table) if you are making a 90% confidence interval with a sample size of 20?
To find the critical t-value for a 90% confidence interval with a sample size of 20, we need to find the degrees of freedom and then locate the value in the t-table.
The degrees of freedom for a one-sample t-test with a sample size of 20 is calculated as (n - 1), where n is the sample size. Therefore, the degrees of freedom will be 19.
To find the critical t-value in the t-table, we need to determine the confidence level and the degrees of freedom. For a 90% confidence level with 19 degrees of freedom, we can look up the critical t-value in the table (or use statistical software).
Using a t-table or a statistical software, the critical t-value for a 90% confidence interval with 19 degrees of freedom is approximately 1.729.