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