If you were told that a sample of 26 breast-fed infants had a mean hemoglobin level of x-bar = 13.9 grams/100 ml with a standard deviation of s = 1.7 g/100ml, give 95% confidence intervals for the mean hemoglobin level of breast-fed infants as indicated below.
a.Calculate the 95% confidence interval assuming that the standard deviation (σ) of the breast-fed infants population (normal distribution) is σ = 2.1g/100ml.
b.Calculate the 95% confidence interval assuming that the standard deviation (σ) of the breast-fed infants population is unknown.