Construct a Confidence Interval For $\mu _ { \mathrm { d } }$

Construct a confidence interval for $\mu _ { \mathrm { d } }$ , the mean of the differences d for the population of paired data. Assume that the
population of paired differences is normally distributed.
-A test of abstract reasoning is given to a random sample of students before and after they completed a formal logic course. The results are given below. Construct a 95% confidence interval for the mean difference between
The before and after scores.

A) $0.2 < \mu _ { \mathrm { d } } < 7.2$
B) $1.2 < \mu _ { \mathrm { d } } < 5.7$
C) $0.8 < \mu _ { \mathrm { d } } < 6.6$
D) $1.0 < \mu _ { \mathrm { d } } < 6.4$