A sample of n = 25 individuals is selected from a population with = 80, and a treatment is administered to the sample. Which outcome is expected if the treatment has no effect?

a.

The sample mean after the treatment should be very different from 80, leading a researcher to reject the null hypothesis.

b.

The sample mean after the treatment should be very different from 80, leading a researcher to fail to reject the null hypothesis.

c.

The sample mean after the treatment should be close to 80, leading a researcher to reject the null hypothesis.

d.

The sample mean after the treatment should be close to 80, leading a researcher to fail to reject the null hypothesis.