‘A drug was given to 10 patients and the increase in blood pressure was recorded to be 3, 6, -2, 4, -3, 4, 6, 0, 0, and 2. Is it reasonable to believe that the drug has no effect on the change of blood pressure?’ Which suitable test statistic can you use?
An appropriate test statistic for evaluating whether the mean change in blood pressure differs from zero is the one-sample t-test. The one-sample t-test is used when you want to determine if the mean of a single sample is significantly different from a known or hypothesized population mean. Since the sample size is small (10 patients) and the population standard deviation is unknown, the t-test is more suitable than the z-test, which is usually applied when the population standard deviation is known and/or the sample size is large.
I am confused!