Question

	Gender
Hair color	male	female	total
Blonde	0	4	4
Brunette	4	4	8
Red	0	1	1
Black	5	1	6
Other	2	1	3
total	11	11	22

Put formulas and answers in yellow shaded cells.

Question
1	P(black hair) =
2	P(blonde hair) =
3	P(male AND brunette hair) =
4	P(red OR black) =
5	P(male OR brunette) =

1) The probability of having black hair.

2) The probability of having blonde hair.

3) The probability of being male and having brunette hair.

4) The probability of having red or black hair.

5) The probability of being male or having brunette hair.

Answer 1

	Gender
Hair color	male	female	total
Blonde	0	4	4
Brunette	4	4	8
Red	0	1	1
Black	5	1	6
Other	2	1	3
total	11	11	22

P(A) = n(E)/n(S)

• P(A) is the probability of an event “A”
• n(E) is the number of favorable outcomes
• n(S) is the total number of events in the sample space

1) The probability of having black hair.

=total number of black hair people/total people under study

=6/22

=0.2727

2)The probability of having blonde hair.

=total number of blonde hair people/total people under study

=4/22

=0.18181

3)  The probability of being male and having brunette hair.

here probability of the intersection of two events has asked both events are dependent

P(A and B)=P(A)*P(B)

=prob(person is male )*prob(his hairs are black)

=(Total Male/Total People)*(male with black hair/total male)

=(11/22)*(5/11)

=5/22

=0.2272

4) The probability of having red or black hair.

here probability of the union of two events has asked both events are dependent

P(A U B)=P(A)+P(B)

P(Red or Black hair)=P(Red hair)+P(Black hair)

=(Total red hair people/total people in sample space)+(Total black hair people/total people in sample space)

=(1/22)+(6/22)

=.03181

5) The probability of being male or having brunette hair.

here probability of the union of two events has asked both events are dependent

P(A U B)=P(A)+P(B)

P(being Male or brunette hair)=P(person is male)+P(he has brunette hair)

=(Total male/total people in sample space)+(people with brunette hair/total people)

=(11/22)+(8/22)

=0.9090