Homework Help: Stats

Posted by Jessica on Wednesday, November 14, 2012 at 5:57pm.

I have a test on this tomorrow and I swear he didn't teach this and the book's not helping either, so maybe u can:

A hwy engineer knows that his crew can lay 5 miles of hwy on a clear day, 2 miles on a rainy day, and only 1 mile on a snowy day. Suppose that the probabilities are as follows:
Outcome prob/random variable: clear .6/5, rain .3/2, snow .1/1
Find the mean (expected value) and the variance

Can anyone at least tell me where to start????

Stats - RD Statistics, Thursday, November 15, 2012 at 12:19am
X P(X) x*P(X) x^2*P(X)
5 0.6 3 15
2 0.3 0.6 1.2
1 0.1 0.1 0.1
Mean = sum x*P(X)=3.7
sum (x^2 * P(X)) = 16.3
Variance = (x^2 * P(X)) - Mean^2
=16.3 - (3.7)^2 = 2.61
Mean = 3.7 miles and variance = 2.61 miles square

Answer this Question

Related Questions

to ms.sue - is there a website where i can take a review test of the test i have...
Chemistry - i dont understand electron affinity and it isnt in our text book at ...
Science 7R - Tomorrow I have a science test on circulatory system and is there ...
8th Grade Chemestry - Helping my child study. Are there any online guides that ...
8th Grade Chemestry - Helping my child study. Are there any online guides that ...
8th Grade Chemestry - Helping my child study. Are there any online guides that ...
AP U.S History - Are there any AP U.S History websites that explain the chapters...
Statistics-Concept Question - I have a stats exam tomorrow and I understand the ...
classroom instruction - how will you teach and talk to students about the war? ...
Algebra II- please help! - I just cannot seem to be able to grasp the concept of...

For Further Reading

First Name:
School Subject:
Answer: