A study of iron deficiency among infants compared different feeding regimens. One group contain breast fed infants, while the other group received a standard baby formula without iron supplements. After six months the hemoglobin levels in the infants' blood were measured. The table summarizes these results.
23 breast fed babies: mean hemoglobin = 13.3 with a st. dev. = 1.7, 19 formula fed babies: mean hemoglobin = 12.4 with a st. dev. = 1.8.
|
Sample Size |
Mean |
Standard Deviation |
|---|
Breast fed |
23 |
13.3 |
1.7 |
|---|
Formula fed |
19 |
12.4 |
1.8 |
|---|
You will be using a 95% level of confidence to estimate the difference in hemoglobin levels between the two groups. You may assume both samples come from normally distributed populations.
Please fill in the blank and answer questions below using the prompt above.
The right hand critical value is . Round to 3 decimal places.
The margin of error, rounded to 3 decimal places, is .
Construct the 95% confidence interval estimate of the difference between the two groups. Round your answers to 2 decimal places.
< difference="" in="" mean="" hemoglobin="" levels="" between="" the="" breast="" fed="" and="" formula="" fed="" babies="">
Do babies on a breast fed diet have higher hemoglobin levels than babies on a formula fed diet. Explain using statistics.
In your explanation, please provide details on determining degree of freedom and what t-table to use. Thank you!