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For problems 4-6 use thefollowing information. Suppose 75% of girls age 5-8 know

ID: 2915640 • Letter: F

Question

For problems 4-6 use thefollowing information. Suppose 75% of girls age 5-8 know whoHannah Montana is. You choose 2 girls at random from this agegroup.

1.     Write down the sample space for thissituation.

2.     You want the probabilitythat BOTH girls know who Hannah Montana is. Write down in probabilitynotation what that phrase means. (No numbers or formulas.)

3.     If you want the probability thatexactly one of the girls knows who HM is, which rule(s) do youhave to use to solve the problem and get your final numericalanswer?

a.     Addition rule and Multiplicationrule

b.     Only the multiplication rule

c.     Only the addition rule

d.     None of the above.

Explanation / Answer

a) The sample space would be all possible groups of 2from girls 5-8 years old. b) Let x = # of girls 5-8 years old who know who HM is. Wewant to find P(x = 2) c) If we want to find P(x = 1) then we would need to useboth the multiplication rule AND the addition rule     [ Since the solution would be (0.75)(0.25)+ (0.25)(0.75) = 0.375]