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 44 couples. Complete parts A to C below.

a. Find the mean and the standard deviation for the numbers of girls in groups of 44 births.

b. Use the range rule of thumb to find the values separating results that are significantly low or significantly high.

value of _____ girls are significantly low.

value of _____ girls are significantly high.

c. Is the result of 41 girls a result that is significantly​ high? What does it suggest about the effectiveness of the​ method?

The result ____ (is / is not) significantly high, because 41 girls is __________ (equal to, greater than, less than) ___ (specific number) girls. A result of 41 girls would suggest that the method ________ (is effective/ is not effective)

Answer 1

a)

here mean of distribution=μ=np=		22
and standard deviation σ=sqrt(np(1-p))=		3.3166~ 3.3

b)

for 2 standard deviation from mean are unusual

value of 15.4 or fewer are significantly low

value of 28.6 or greater are significantly higher

c)

The result is significantly high, because 41 girls is greater than 28.6 girls. A result of 41 girls would suggest that the method is effective