I am having trouble finding the correct equation to use in my textbook. The formula I used gave me the answer of 12 but I have a feeling this is incorrect.

When solving, can you please label the variables and show work. I'd like to truly understand the formula for future assignments.

True or False?

Assume a researcher recruits 150 African American and Caucasian individuals taking warfarin to determine if there is a difference in the mean dosage of the medication needed to cause a decrease in their INR blood test. If the mean dosage for 75 Caucasian individuals required to get their INR blood test in range is 6.1 mg with a standard deviation of 1.7 mg and the mean dosage for 75 African American individuals required to get their INR blood test in range is 4.3 mg with a standard deviation of 0.9 mg, the S_p value obtained while calculating the test statistic is approximately 1.10 mg.

Thank you!!