10.1 Confidence Interval Estimates of Two INDEPENDENT Means 1. 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. Sample Size Mean Standard Deviation Breast fed 23 13.3 1.7 Formula fed 19 12.4 1.8 Use 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. Do babies on a breast fed diet have higher hemoglobin levels than babies on a formula fed diet? Explain using statistics.10.3 CI Estimates Of TWO PAIRED Means 1. Ten randomly selected cars were filled with either regular or premium gas (the decision was made based on a coin toss) and then driven on the freeway for the entirety of the tank of gas. The next day, each car was filled with whichever type of gas that was not used the previous day and then driven on the freeway for the entirety of the tank of gas. The mileage for each day was recorded and is summarized in the table below. Car 1 Car 2 Car 3 Car 4 Car 5 Car 6 Car 7 Car 8 Car 9 Car 10 Regular 16 20 21 23 27 27 25 27 28 22 Premium 19 22 24 25 25 24 Construct a 90%% confidence interval estimate of the difference between the mean efficiency of the car using regular and premium gas. You may assume that both samples are drawn from normally distributed populations. Is premium gas really more efficient? Justify your answer with statistics.10.2 CI Estimate of Two Proportions 1. The herb ginkgo biloba is commonly used as a treatment to prevent dementia, In a study of the effectiveness of this treatment, 1545 elderly subjects were given ginkgo and 1524 were given a placebo. Among those in the ginkgo treatment group, 246 later developed dementia, and among those in the placebo, 277 later developed dementia. C a 99% confidence interval estimate of the difference between the proportion of subjects that developed dementia who received ginkgo and those who did not. Does ginkgo appear to reduce dementia? Explain using statistics