Our World Statistics Day conversations have been a great reminder of how much statistics can inform our lives. Do you have an example of how statistics has made a difference in your life? Share your story with the Community!
Choose Language Hide Translation Bar
Highlighted
rs
rs
Level II

Why is the prediction interval (individual) getting larger with larger sample size?

Hi All,

 

I am using JMP14 to calculate the prediction  interval of individuals.  On the figure below you will see:

 

n=1             PI  (     74.5  - 125.5)

n=10           PI  (  63.5     -    136.5)

n=100,000   PI  (34.6       -        165.4)

 

Should the PI (individual) interval get narrower  as the PI (mean)?

 

Thx

 

image.png

1 ACCEPTED SOLUTION

Accepted Solutions
Highlighted
phil_kay
Staff

Re: Why is the prediction interval (individual) getting larger with larger sample size?

Hi,

 

I think this is a misunderstanding about prediction intervals. The intervals get wider with higher N because these are intervals within which you expect to find all N observations. I found this white paper really useful in understanding the differences between confidence, prediction and tolerance intervals.

 

Hope that helps.

Phil

View solution in original post

2 REPLIES 2
Highlighted
phil_kay
Staff

Re: Why is the prediction interval (individual) getting larger with larger sample size?

Hi,

 

I think this is a misunderstanding about prediction intervals. The intervals get wider with higher N because these are intervals within which you expect to find all N observations. I found this white paper really useful in understanding the differences between confidence, prediction and tolerance intervals.

 

Hope that helps.

Phil

View solution in original post

Highlighted
rs
rs
Level II

Re: Why is the prediction interval (individual) getting larger with larger sample size?

Thank you Phil!

Article Labels

    There are no labels assigned to this post.