A research report includes the statement, “z 5 2.18, p , .05.” What happened in the hypothesis test?

a. The obtained sample mean was very unlikely if the null hypothesis is true, so H0 was rejected.

b. The obtained sample mean was very likely if the null hypothesis is true, so H0 was rejected.

c. The obtained sample mean was very unlikely if the null hypothesis is true, and the test failed to reject H0.

d. The obtained sample mean was very likely if the null hypothesis is true, and the test failed to reject H0.