Assume that different groups of couples use a particular method of gender select
ID: 3315873 • Letter: A
Question
Assume that different groups of couples use a particular method of gender selection and each couple gives birth to one baby. This method is designed to increase the likelihood that each baby will be a girl, but assume that the method has no effect, so the probability of a girl is 0.5. Assume that the groups consist of 45 couples. Find the value of the mean. Find the value of the standard deviation. Use the range rule of thumb to find the values separating results that are significantly low or significantly high. Is the result of 37 girls a result that is significantly high? What does it suggest about the effectiveness of the method?
Explanation / Answer
here from binomial distribution
mean=np =45*0.5=22.5
std deviation =(np(1-p))1/2 =3.354
as we know from range rule of thumb that two std deviation with value from mean are usual
hence range of usual values =mean -/+ 2*std deviation =22.5 -/+ 2*3.354 =15.79 ; 29.21
as 37 girls falls outside range of usual values therefore is significantly very high
it ssuggest that method is effective