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 22 couples. Complete parts (a) through (c) below.
a. Find the mean and the standard deviation for the numbers of girls in groups of 22 births.
The value of the mean is muequals
11.
(Type an integer or a decimal. Do not round.)
The value of the standard deviation is sigmaequals
nothing.
(Round to one decimal place as needed.)
b. Use the range rule of thumb to find the values separating results that are significantly low or significantly high.
Values of
nothing girls or fewer are significantly low.
(Round to one decimal place as needed.)
Values of
nothing girls or greater are significantly high.
(Round to one decimal place as needed.)
c. Is the result of 18 girls a result that is significantly high? What does it suggest about the effectiveness of the method?
The result
is
significantly high, because 18 girls is
less than
greater than
less than
equal to

29.3 girls. A result of 18 girls would suggest that the method
is not effective.
is not effective.
is effective.
(Round to one decimal place as needed.)