Expected value from triangle distribution

[spot]

Hi, I had this triangle distribution and I wanted to check if my answer was correct for the expected value

For the y intercept, I got 2/15 and the equation for p(x) was therefore -1/450 x + 1/15
After integrating x p(x), I got 10 as the expected value. Could someone please check if this is correct?
Thanks

 

[tkhunny]

Hi, I had this triangle distribution and I wanted to check if my answer was correct for the expected valueView attachment 10765

For the y intercept, I got 2/15 and the equation for p(x) was therefore -1/450 x + 1/15
After integrating x p(x), I got 10 as the expected value. Could someone please check if this is correct?
Thanks

Except for the "I got 2/15", it is fine. Why do you doubt? Does that seem reasonable?

One for free. Next time, actually show your work.

 

[spot]

Thanks for the reply
Actually, I just realised I miscopied the intercept. What I meant to write was 2/30 (which is 1/15). The way I calculated this was due to the whole area being equal to 1, so (1/30)*2 gives you the height of the triangle.
I guess my doubt comes from being unable to check whether my answer is correct

 

[tkhunny]

Thanks for the reply
Actually, I just realised I miscopied the intercept. What I meant to write was 2/30 (which is 1/15). The way I calculated this was due to the whole area being equal to 1, so (1/30)*2 gives you the height of the triangle.
I guess my doubt comes from being unable to check whether my answer is correct

Gaining confidence is part of what you should be doing. Good work.

I was going to ask how you computed the intercept. If you said you found the integral over that region, I was going to scowl and shake my head in your general direction. Good work seeing it was just a triangle. ½ * 30 * Height = 1 ==> Height = 1/15

 

[JeffM]

Thanks for the reply
Actually, I just realised I miscopied the intercept. What I meant to write was 2/30 (which is 1/15). The way I calculated this was due to the whole area being equal to 1, so (1/30)*2 gives you the height of the triangle.

Well done.

 

[spot]

I actually did it by integration first, then I was looking around here (to see someone else also getting scowled at in another thread!) and I figured I could've done it without, so that's what I did

 

[tkhunny]

I actually did it by integration first, then I was looking around here (to see someone else also getting scowled at in another thread!) and I figured I could've done it without, so that's what I did

haha This is how we learn.