Stats

posted by .

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 -

    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

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. U.S History

    HWy did the Americans begin to settle in the Southwest?
  2. physic

    Lai was driving north on Hwy 75 with a speed of 56.9 m/s when she heard on a CB that a patrolman was hiding 127.3 m north of where she is. Knowing that the patrolman can start clocking the car in 2.7 seconds, Lai decided to slow to …
  3. to ms.sue

    is there a website where i can take a review test of the test i have heard of a land because i forgot to take my practice book home and tomorrow is the test.
  4. statistics

    List below are the duration (in hours) of a simple random sample of all flights of a space shuttle program. Find the range, variance, and standard deviation for the sample data. Is the lowest duration time unusual?
  5. Stats Class

    The EPA city/hwy mpg range for a Saturn Vue FWD automatic 5-speed transmission is 20 to 28 mpg. If you owned this vehicle, how large a sample (e.g. how many tanks of gas) would be required to estimate your mean mpg with an error of …
  6. Stats

    So i have a test in stats tomorrow and im trying to work on my study guide but im stuck at this question : Construct a confidence interval for the proportion for each case 90 percent interval 861 out of 2500. please help.
  7. math

    A construction crew is lengthening a road. The road started with a length of 56 miles, and the crew is adding 3 miles to the road each day. Let L represent the total length of the road (in miles), and let D represent the number of …
  8. Life orientation

    Identify three human right violation and explain in introductory paragraph hwy you choose the specific human right violation
  9. College Algebra

    ok, so I need to come up with an answer for this question- A car traveling 65mph on the hwy gets 25 miles per gallon. Write the function that represents the distance d(t) in miles that the car travels in t hours. *Then, Write a function …
  10. Math

    Donald Trump purchased a large box of his own books for $55,000. He gave 25 of the books to other republican nominees and then sold the rest on an Internet website for $63,000, making a profit of $15 on each one. a) How many his books …

More Similar Questions