HELPPP: find λ

obh

Active Member
#2
What distribution? exponential?
What did you try to do? (hint, adding ln to both size of the equation, ln(x^y) = y ∙ ln(x))
 
#7
How? I'm thinking this is a statistics class assignment. You could use Excel GoalSeek in a more general case, but I think that probably the tables solution is the one wanted here because the answer comes out exactly to a nice round number.
 

obh

Active Member
#8
Yes, it looks like assignment. But they should stop using old tables in assignments! it doesn't make sense.
like they don't use slide rules anymore ...
 
#9
It's not an easy problem without special software. Try to find λ given that P(X>4) = 0.1
So, Shaolu, are you working with tables?
 
#16
You may also do a loop in R, I just used brute force ... a binary search would be more elegant

q=0.0527
x=4
#-----
p=1
delta=0.01
p1=1-q

lambda=0.01
while (p>p1)
{
lambda=lambda+delta
p=ppois(x,lambda)
}
lambda-delta
 

Dason

Ambassador to the humans
#18
I don't hate tables. Part of the course typically is learning how to read charts and graphs. The tables really aren't that complex and a student should be able to understand them.
 
#19
I really don't hate tables, and I also liked to play with my grand father's slide ruler when I was a kid.
But I think it is important to learn to use the tables exactly as it is important to learn to use the slide rule.
Where is the next slide rule class? :)

slide_rule.jpg