Question

According to a 1996 report on full-term pregnancies by the American Medical Association, women pregnant with twins who received intensive prenatal care had an infant mortality rate of 5.4 deaths per thousand live births, while women pregnant with twins who received only adequate care had an infant mortality rate of 3.9 deaths per thousand live births. Does this suggest that a woman pregnant with twins should be concerned about seeking too much medical care? Explain fully in one or two complete sentences.

Answer 1

Given the proportions of deaths

= 5.4/1000 = 0.0054

= 3.9/1000 = 0.0039

Now to decide that a woman pregnant with twins should be concerned about seeking too much medical care,

we can check if deaths with intense parental care and adequate care are significantly different or not.

This corresponds to a right-tailed test, for which a z-test for two population proportions needs to be conducted.

Take the significance level as 0.05.

pooled proportion = 5.4+3.9/2000 = 0.00465

Standard error (SE) = =

= 0.003

Z-statistic would be = (0.0054 - 0.0039)/0.003 = 0.5

For this z-statistic, p-value comes out to be 0.308

Since p > 0.05

Hence we do not have strong evidence against the null hypothesis.

The null hypothesis Ho is not rejected. therefore we can be 95% confident that p1 = p2.

This does not suggest that a woman pregnant with twins should be concerned about seeking too much medical care.