# Recent content by snoggerT

1. ### Density Function and E(x)

- Thanks. I wasn't quite grasping what i was being told at first, but as soon as you put both equations up, I knew what to do.
2. ### Density Function and E(x)

- I haven't been able to figure it out with what you said. I know that the probability density function equation is the integral from a to b of f(x)dx, but I'm not sure how to relate that to the E(X) formula.
3. ### Density Function and E(x)

Density Function and E(x)[solved] The density function of X is given by https://webwork.math.lsu.edu/webwork2_files/tmp/equations/48/83b2bf602cc895a007a673a9a23c3c1.png If the expectation of X is E(X)=-1, find a and b. The Attempt at a Solution I'm actually working ahead of the...
4. ### Probability of current flow through circuit

- That is what I tried using actually, but I guess I'm not quite sure how to set up the formula once you get past 3 events.
5. ### Probability of current flow through circuit

The probability of the closing of the ith relay in the circuits shown is given by p_i. Let p_1 = 0.9, p_2 = 0.6, p_3 = 0.1, p_4 = 0.7, p_5 = 0.2. If all relays function independently. what is the probability that a current flows between A and B for the respective circuits...
6. ### Expected Value (probability problem)

Alright, I figured it out. The $800,000 value is supposed to be$800. So I suppose my professor made a typo when setting the problem up.
7. ### Expected Value (probability problem)

- yeah, I'm at a loss. Maybe the numbers are showing up wrong in relation to the actual answer.
8. ### Expected Value (probability problem)

- I copied the values straight from the webwork homework. I do find it very odd that the numbers go from $10,000 @ 1/4,000,000 chance to$800,000 @ 1/500,000 chance. But here is how I worked the problem: E(X) =...
9. ### Expected Value (probability problem)

Prizes and the chances of winning in a sweepstakes are given in the table below. Prize: Chances $25,000,000: 1 chance in 400,000,000$250,000: 1 chance in 150,000,000 $75,000: 1 chance in 50,000,000$10,000: 1 chance in 4,000,000 \$800,000: 1 chance in...
10. ### Mean and standard deviation problem

- I get it. Can you explain the standard deviation portion for me? for instance, when v=8x, the standard deviation is 8*4, but I'm not sure why. Is x the standard deviation in the equation?
11. ### Mean and standard deviation problem

The mean and standard deviation of a random variable x are -11 and 4 respectively. Find the mean and standard deviation of the given random variables: 1) y=x+7 2) v=8x 3) w=8x+7 2. Homework Equations : E(x) = u, E(ax+b) = aE(x)+b The Attempt at a Solution I've gotten...
12. ### Defining probability events

-Ahh, well, I'm going to keep messing with this and see if I can't figure it out. I used the reduction of sample space for another part of the problem in which C was part of the subset of D, so P(D)/P(B) was valid. That won't work with the other 2 problems though. I don't recall ever...
13. ### Defining probability events

- Right. So I must be doing my math wrong for the actual problems. For instance, https://webwork.math.lsu.edu/webwork2_files/tmp/equations/b2/d7de36f0f41c31b27bcb1db8fe7cc21.png=[/URL] 1 - P(D|B) but I'm not getting the correct answer. So I must be doing something wrong in my math...
14. ### Defining probability events

Do you not agree with one of the others I have done?
15. ### Defining probability events

I end up getting: A = 1/3 B = 2/6*4/5 + 4/6*2/5 + 2/6*1/5 = 3/5 C = 3/6*2/5 = 1/5 D = 2/6*1/5 + 3/6*2/5 = 4/15 I'm positive C and D are right because the problem involving just those 2 was correct. I don't believe that B is right though, because I can't get the right answers with what...