(Solved): Six randomly selected students took an IQ test A, and the next day they took a very similar IQ test ...

Six randomly selected students took an IQ test A, and the next day they took a very similar IQ test B. Their scores are shown in the table below. The difference in the IQ scores (Test A- Test B) for this sample results in $\stackrel{?}{d}=?1$ and $s_d=2.19$ Assume that the reading speeds are approximately normally distributed. On average, do people score better on the second test than in the first test they take? One wishes to test $H_0:{?}_d=0H_a:{?}_d<0$ Find the rejection region for the above test with $?=05$. $\begin{array}{l}(??,?2.015)\\ (??,2.015)\\ (1.96,?)\\ (??,?1.645)\\ (1.645,?)\end{array}$