Comments on: Automatically calculate confidence intervals in Excel

By: J

Tue, 26 May 2009 09:31:11 +0000

Hi,
You have errors in this,
your CLs are not the percentages they aspire to be.

See below for first two examples

r1 250.56 236.68
r2 258.81 234.76
r3 249.73 231.23
r4 253.50 238.37
r5 247.10 222.11

n 5.00 5.00
stdev 4.47 6.45
mean 251.94 232.63

0.1 3.29 4.75
0.05 3.92 5.66
0.01 5.15 7.43

C.L 90% 251.94 ± 3.29 232.63 ± 4.75
C.L 95% 3.29 ± 3.92 4.75 ± 5.66
C.L 99% 3.92 ± 5.15 5.66 ± 7.43

By: Irfan

Irfan — Sun, 08 Mar 2009 10:09:35 +0000

Dear

Congrats for your hardwork.But friends I want one help how can I create a formula to find the exact time intervals , the time taken by employee.

Example: The Lunch Break is for one hour assume 1:00 PM to 2:00 PM If employee comes by 2:15 PM How can I make it.

By: Jeroen

Jeroen — Mon, 02 Feb 2009 16:42:26 +0000

I’m not a statistician by any means, so correct me if I’m wrong, but there seems to be an error in your macro:

confint = stderr * Application.TInv((1 – conflvl), n)
should imo be
confint = stderr * Application.TInv((1 – conflvl), (n-1))

The reason for this is that TINV takes degrees of freedom as input and NOT sample size. For a sample of size n, the t distribution will have n-1 degrees of freedom.

By: Jenna

Jenna — Mon, 05 Jan 2009 03:08:04 +0000

Thank you so much for this – a friend needed help, and this little macro let me wrap up everything in 2 hours! I was already thinking I was in for a big haul…

By: Balaji P.G

Balaji P.G — Wed, 22 Oct 2008 10:49:26 +0000

That was real quick update…BTW may i know your name and what you are doing? I am Balaji P.G and a research scholar working towards my PhD in National University of Singapore

By: Jesper

Jesper — Wed, 22 Oct 2008 09:25:23 +0000

You are absolutely correct. I will update my post to reflect this.

Thanks!

By: Balaji P.G

Balaji P.G — Wed, 22 Oct 2008 08:25:53 +0000

hi,

I disagree with your comment that there is no native comment. There is a comment called as Confidence(alpha, Standard deviation, size) which calculates confidence interval.