ɑ=1-0.95=0.05.
Degrees of freedom=50-1=49. 1-ɑ/2=0.975, the critical probability, corresponding to a critical value of 2.01.
Standard error=SD/√n=0.21/√50=0.0297, rounded to 0.03.
Margin of error=2.01×0.03=0.06 approx.
Confidence interval is 1.8±0.06=1.74≤1.80≤1.86 oz.