#4

Five males with anX-linked genetic disorder have one child each. The random variable x is the number of children among the five who inherit theX-linked genetic disorder. Determine whether a probability distribution is given. If a probability distribution isgiven, find its mean and standard deviation. If a probability distribution is notgiven, identify the requirements that are not satisfied.

x P(x)

0 0.031

1 0.153

2 0.316

3 0.316

4 0.153

5 0.031

Does the table show a probabilitydistribution? Select all that apply.

A. Yes, the table shows a probability distribution.

B. No, the sum of all the probabilities is not equal to 1.

C. No, the random variable x is categorical instead of numerical.

D. No, the random variablex's number values are not associated with probabilities.

E. No, not every probability is between 0 and 1 inclusive.

Find the mean of the random variable x. Select the correct choice belowand, ifnecessary, fill in the answer box to complete your choice.

A. = _______ child(ren) (Round to one decimal place asneeded.)

B. The table does not show a probability distribution.

Find the standard deviation of the random variable x. Select the correct choice belowand, ifnecessary, fill in the answer box to complete your choice.

A. = ______ child(ren) (Round to one decimal place asneeded.)

B. The table does not show a probability distribution.

#9

Multiple-choice questions each have five possible answers (a,b,c,d,e), one of which is correct. Assume that you guess the answers to three such questions.

a. Use the multiplication rule to find P(WCW), where C denotes a correct answer and W denotes a wrong answer.

P(WCW)= _______ (Type an exactanswer.)

b. Beginning with WCW, make a complete list of the different possible arrangements of one correct answer and two wrong answers, then find the probability for each entry in the list.

P(WCW)see above

P(CWW)= _______

P(WWC)= _______

(Type exactanswers.)

c. Based on the precedingresults, what is the probability of getting exactly one correct answer when three guesses aremade?

______ (Type an exactanswer.)

#10

A survey showed that 77% of adults need correction(eyeglasses, contacts,surgery, etc.) for their eyesight. If 13 adults are randomlyselected, find the probability that nomorethan 1 of them need correction for their eyesight. Is 1 a significantly low number of adults requiring eyesightcorrection?

The probability that nomorethan 1 of the 13 adults require eyesight correction is _____.

(Round to three decimal places asneeded.)

Is 1 a significantly low number of adults requiring eyesightcorrection? Note that a small probability is one that is less than 0.05.

A. No, because the probability of this occurring is small.

B. Yes, because the probability of this occurring isnot small.

C. No, because the probability of this occurring isnot small.

D. Yes, because the probability of this occurring is small.

#11

Based on apoll, among adults who regret gettingtattoos, 28% say that they were too young when they got their tattoos. Assume that eight adults who regret getting tattoos are randomlyselected, and find the indicated probability. Complete parts(a) through(d) below.

a. Find the probability that none of the selected adults say that they were too young to get tattoos.

_______ (Round to four decimal places asneeded.)

b. Find the probability that exactly one of the selected adults says that he or she was too young to get tattoos.

_______ (Round to four decimal places asneeded.)

c. Find the probability that the number of selected adults saying they were too young is 0 or 1.

_______ (Round to four decimal places asneeded.)

d. If we randomly select eight adults, is 1 a significantly low number who say that they were too young to gettattoos?

______ ( A. No B. Yes) because the probability that ______( A. less than 1, B. at least 1, C. more than 1, D. exactly 1, E. at most 1) of the selected adults say that they were too young is ________ (A. greater than, B. equal to C. less than) 0.05.

#12

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 39 couples. Complete parts(a) through(c) below.

a. Find the mean and the standard deviation for the numbers of girls in groups of 39 births.

The value of the mean is =______.

(Type 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 37 girls a result that is significantlyhigh? What does it suggest about the effectiveness of themethod?

The result _______ (A. is, B. is not) significantlyhigh, because 37 girls is ______ (A. greater than, B. less than, C. equal to) _____ girls. A result of 37 girls would suggest that the method _______ (A. is not effective, B. is effective).

(Round to one decimal place asneeded.)