Question

Given tGiven the following probability distribution, find P (X = 3).

X 1 2 3 4 5
P(X) 0.4 0.1 0.15 0.2
(1 point)

2. The number of cars an American family owns follows the distribution below:

Number of Cars 0 1 2 3 4 5
Probability 0.09 0.36 0.35 0.13 0.05 0.02


a) Verify that this is a legitimate probability distribution.
b) Interpret (in words) the notation P(X > 2).
c) Interpret (in words) the notation P(X = 2).
d) Find P(X > 2). (5 points)

3. A study of social mobility in America examined the social class attained by the sons of lower class fathers. Social classes were numbered from 1 to 5 with 1 representing the lower class and 5 the higher class. Consider the random variable X to the class of a randomly chosen son. The study found the following distribution:

Son's Class 1 2 3 4 5
Probability 0.48 0.38 0.08 0.05 0.01

a) What percent of the sons reached the highest class?
b) Check that this distribution meets the requirements of a discrete probability distribution.
c) What is P(X < 2)?
d) What is P(X = 2)?
e) Write the event: a son of a lower-class father attains one of the highest two social classes in terms of X. (6 points)

Answer 1

a trick for getting quick help : limit to one question per post

Answer 2

for 1st question, use below :
sum of probabilities must add up to 1

Answer 3

X 1 2 3 4 5
P(X) 0.4 0.1 0.15 0.2 <<<<<<<<<

Answer 4

that row must add up to "1"

Answer 5

0.4 + 0.1 + P(3) + 0.15 + 0.2 = 1

Answer 6

solve P(3)

Answer 7

ok thanks

Answer 8

np :) did u solve P(3) ha...

Answer 9

so add all the numbers together?

Answer 10

yes

Answer 11

0.4 + 0.1 + P(3) + 0.15 + 0.2 = 1

P(3) + 0.85 = 1

P(3) = 0.15

Answer 12

see if that makes more or less sense :)

Answer 13

15

Answer 14

0.15

Answer 15

*its 0.15

Answer 16

yup

Answer 17

hey i need to go... please post the second question in a separate post... good luck !

Answer 18

ok thanks

Answer 19

np :)