Question

For several​ years, evidence had been mounting that folic acid reduces major birth defects. In a​ study, doctors enrolled women prior to conception and divided them randomly into two groups. One​ group, consisting of 2722 ​women, took daily multivitamins containing 0.8 mg of folic​ acid; the other​ group, consisting of 2107 ​women, received only trace elements. Major birth defects occurred in 31 cases when the women took folic acid and in 47 cases when the women did not. a. At the 1​% significance​ level, do the data provide sufficient evidence to conclude that women who take folic acid are at lesser risk of having children with major birth​ defects? b. Is this study a designed experiment or an observational​ study? Explain your answer.

Calculate the test ​(Round to two decimal place

Answer 1

Let sample 1: women took folic acid

sample 2: women did not take folic acid

(a)

At the 1​% significance​ level, the data provides sufficient evidence to conclude that women who take folic acid are at lesser risk of having children with major birth​defects.

(b)

Study is experimental study because researcher gave some treatment to some women.