Question 1162463
this is a 95% t-interval with x bar 12, s=1.9 min, and n=49
t 0.975, df=48=2.01
half-interval is 2.01*s/sqrt(n)=2.01*1.90/7=0.545
the 95% CI is (11.45, 12.55) min
for 99%, t=2.68
half-interval is 2.68*1.9/7=0.727 or 0.73
99% interval is (11.27, 12.73) min