Calculate d overbar. d overbarequals 0.309 (Type an integer or a decimal. Round to three decimal places as needed.) Part 6 Calculate s Subscript d. s Subscript dequals 0.485 (Type an integer or a decimal. Round to three decimal places as needed.) Part 7 (d) Use the t-test to find the standardized test statistic t. tequals 2.115 (Type an integer or a decimal. Round to three decimal places as needed.) Part 8 (e) Decide whether to reject or fail to reject the null hypothesis. Choose the correct answer below. Fail to reject the null hypothesis. Reject the null hypothesis