a. A researcher is conducting a hypothesis test for a difference in means using two samples, one of size n₁ = 23 and the other of sizen₂ = 18. The pooled standard deviation was found to bes_Pool = 5.1. What is thestandard error for the difference in means? Round your answer to 3 decimal places as needed.

b. On the way to using a mathematical model to test the null hypothesis that the difference in means between two groups equals zero, a researcher calculates a pooled standard deviation ofs_Pool = 6.7. Use this as well as the information in the table below to calculate the T value (find the difference as group 1 minus group 2). Round your answer to 3 decimal places as necessary.

group 1: sample mean 5.5 sample size 11

group 2: sample mean 5.4 sample size 24

c. Use the information in the table below to calculate theT score for testing the null hypothesis that the difference in means between groups equals zero. Find the difference using group 1 minus group 2. Round your final answer to 3 decimal places as needed.

group 1: sample mean 8.1 standard deviation 3.5 sample size 27

group 2: sample mean 5.7 s.d. 4.7 sample size 26