# Search results

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...
16. ### Defining probability events

- I'm still trying to completely understand the logic in adding 1/6 to 5/6*1/5. I understand that 1/6 is the probability of the 1st ball being yellow, but I'm not sure if I have the logic with the 2nd ball right. I take it as that there is a 5/6 probability of the 1st ball not being yellow...
17. ### Defining probability events

- I'm not having much luck with this, I still can't seem to get the right answers. I'm not sure what I'm missing here.
18. ### Defining probability events

I get: A = 10/35 B (compliment) = 15/35 C = 9/35 D = 13/35 and D (compliment) = 22/35 but I can't get the right answer with the problems I posted a few post back.
19. ### Defining probability events

RR = 4 and GG = 9
20. ### Defining probability events

- I would assume that for D, you would ignore the YY column since that is not possible given that only 1 of the balls is yellow? I'm not getting the correct answers for the actual problem portion...
21. ### Defining probability events

Still haven't been able to figure this out, can anyone help?
22. ### Defining probability events

A box contains one yellow, two red, and three green balls. Two balls are randomly chosen without replacement. Define the following events: A: \{ One of the balls is yellow \} B: \{ At least one ball is red \} C: \{ Both balls are green \} D: \{ Both balls are of the same color \} The...
23. ### Probability defective computer problem

- The first part is right, but I'm not exactly sure on why yet. Can you maybe elaborate a little more?
24. ### Probability defective computer problem

A computer retail store has 14 personal computers in stock. A buyer wants to purchase 3 of them. Unknown to either the retail store or the buyer, 3 of the computers in stock have defective hard drives. Assume that the computers are selected at random. What is the probability that exactly one...
25. ### Elementry Probability problem

I finally got it right. Here is how it works: 1-(38+30+18-13-6-8+4)/98 = 1 - (63/98) = 35/98 (for one student). For 2 students: 35*34/98*97 = 1190/9506 = 12.5% thanks for the help
26. ### Elementry Probability problem

I just got home and looked over the post. Everyone seems to be going in the same direction I was going in, but still no right answer. CaptainEvil - your final answer of 63.2% was not correct. Jonathan G- I had already came to the same answer you had, but it's not right either. So...
27. ### Elementry Probability problem

An elementary school is offering 3 language classes: one in Spanish, one in French, and one in German. These classes are open to any of the 98 students in the school. There are 38 in the Spanish class, 30 in the French class, and 18 in the German class. There are 13 students that in both Spanish...
28. ### Outputting to the parallel port (assembly 8086)

Can any of you think of why only 2 groups out of 15 would have a problem using port 378H? Even using the simple code I posted above is not working.
29. ### Outputting to the parallel port (assembly 8086)

Well, we think the port address issue is why the program won't work. Every other person in the class has had it work fine using port 378H except our group and one other, and they are having the same problem as we are. We even compiled/ran a friends program that worked at his lab station, but...
30. ### Outputting to the parallel port (assembly 8086)

So I'm having a problem in some code I'm working on in Assembly(8086). I've tried everything I can think of, but I can't seem to figure out the problem. So I have a circuit that I built with a DB25 plug so that it can communicate with the parallel port on the computer. All we had to do is...