A computer program has produced the following output for a hypothesis-testing problem:

Difference in sample means: 2.35 Degrees of freedom: 18 Standard error of the difference in sample means: ?

Test statistic: t0 = 2.01 P-value: 0.0298

(a) What is the missing value for the standard error?

(b) Is this a two-sided or a one-sided test?

(c) If ???? = 0.05, what are your conclusions?

(d) Find a 90% two-sided CI on the difference in means.