Question

A study of iron deficiency among infants compared samples of infants following different feeding regimens. One group contained breast-fed infants, while the infants in another group were fed a standard baby formula without any iron supplements. Here are summary results on blood hemoglobin levels at 12 months of age. Group n x s Breast-fed23 13.3 1.6 Formula 20 12.7 1.7 Carry out a t test. Give the P-value. (Use α = 0.01. Use μbreast-fed − μformula. Round your value for t to three decimal places, and round your P-value to four decimal places.)

t=

p-value=

Give a 95% confidence interval for the mean difference in hemoglobin level between the two populations of infants. (Round your answers to three decimal places.)

Answer 1

Given that,

For breast fed :

For formula :

The null and alternative hypotheses are,

Using TI-84 calculator we get,

Test statistic is,

t = 1.186

p-value = 0.2426

The 95% confidence interval for the mean difference in hemoglobin level between the two populations of infants is,

( -0.423, 1.623 )