If a treatment produces a sample mean of M = 25 with s = 18 among a sample of n = 36, which t-statistic should be obtained and which decision should be made if conducting a two-tailed hypothesis test with = 0.05 and an expected mean of = 30?

a.

t = 1.67 and reject H₀

b.

t = 1.39 and reject H₀

c.

t = 1.67 and fail to reject H₀

d.

t = 1.39 and fail to reject H₀