The test procedure, called the two-proportion z-test, is appropriate when the following conditions are met
(a)The sampling method for each population is simple random sampling.
(b)The samples are independent.
The null hypothesis state that there is no difference in population proportion
The alternative hypothesis state that there is a significant difference between proportions.
The test statistic is defined is as follows:
If the test statistic is greater than z- critical. Reject the null hypothesis.
Iron is very important for babies' growth. A common belief is that breastfeeding will help the baby to get more iron than formula feeding. To justify the belief, a study followed 2 groups of babies from born to 6 months. With one group babies are breast fed, and the other group are formula fed without iron supplements. Data below shows iron levels of those two groups of babies.
(1) There are two groups we need to compare for the study: Breast-Fed and Formula- Fed. Are those two groups dependent or independent? Based on your answer, what inference procedure should we apply for this research?
(2) Please perform the inference you decided in (1), and make sure to follow the 5-step procedure for any hypothesis test.
(3) Based on your conclusion in (2), what kind of error could you make? Explain the type of error using the context words for this research