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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 agirl, but assume that the method has noeffect, so the probability of a girl is 0.5. Assume that the groups consist of 30 couples. Complete parts(a) through(c) below.

a. Find the mean and the standard deviation for the numbers of girls in groups of 30 births.

The value of the mean is =

( an integer or a decimal. Do notround.)

The value of the standard deviation is =

(Round to one decimal place asneeded.)

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

Values of girls or fewer are significantly low.

(Round to one decimal place asneeded.)

Values of girls or greater are significantly high.

(Round to one decimal place asneeded.)

c. Is the result of 25 girls a result that is significantlyhigh? What does it suggest about the effectiveness of themethod?

The result

is

is not

significantlyhigh, because 25 girls is

less than

greater than

equal to girls. A result of 25 girls would suggest that the method

is effective.

is not effective.

(Round to one decimal place asneeded.)