Mat120.6195 Homework # 3
Date_4_/15__/07__
Student’s Name:_________IVETTE_URBINA_______________________________
1. A pollster contacts 104 people in the 15-19 age bracket and finds that 80 participate in
religious ceremonies and 24 do not participate in religious ceremonies. When 196 people
in the 20 – 26 age bracket are contacted, 160 participate in religious ceremonies and 36
do not participate in religious ceremonies. If 1 of the 300 people are selected, find:
a) the probability that someone is in the age bracket 20 – 26 and participate in religious
ceremonies.
Answer:______436/300__________________________________
b) the probability that someone is in the age bracket 20 – 26 or participate in religious
ceremonies.
Answer:_______276/300______________________________________
2) Circle the event(s) that can be classified as random variables.
(a) Junia is pregnant. She is expected a baby girl.
b) Mike’s weekly salary is $290.
(c) Bob won $20,000 playing the lotto.
d) Tim bought 2 new suits last week.
3. The table below represents the use of credit card for the past seven days for a sample
of seven students.
x
0
1
2
3
4
P(x)
0.16
0.24
0.40
0.16
0.04
X*p(x)
0
0.24
0.8
0.48
0.16
x(2)
0
1
4
9
16
X(2)(px)
0
0.24
1.6
1.44
0.64
a) Does the table constitute a probability distribution? Why or why not?
Answer:_________yes,_because_when_you_add_(p)(x)_it_equals_to_1._____________
_______________
b) Find the mean and the standard deviation of x.
mean M=1.68
Standard Deviation 1.04766