A random sample of 10 observations is taken from a normal distribution with unknown mean ų and unknown variance. The sample mean is calculated to be 19.78 and the sample variance is calculated to be 0.811. Test at the 5% level of significance the claim that u < 20.
My answer booklet says to reject H0 for H1, and I have no idea why.
Could someone please help? it would be much appreciated.