Sample statistics Normal CI Student t-distribution CI
sample size n 30 left area (percent) p 0.025 tc 2.05
sample mean x̅ 50 right area p 0.975 margin of error E 7.09
standard dev sx 19 lower limit pop mean 43.2 lower limit pop mean 42.91
standard error of the mean 3.47 upper limit pop mean 56.8 upper limit pop mean 57.09
confidence level 0.95 margin of error E 6.80







Normal distribution:
43.2 ≤ µ ≤ 56.8
50 ± 6.8
Student t-distribution:
42.91 ≤ µ ≤ 57.09
50 ± 7.09