Doh! Thanks very much. sg
On 11/6/23 5:17 PM, John Fox wrote:
Dear Spencer,
You need the t distribution with correct df, not the standard-normal
distribution:
> pt(-z.confInt/2, df=13)
1 2 3 4 5 6 7 8 9 10 11
0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025
12 13
0.025 0.025
> pt(-z.predInt/2, df=13)
1 2 3 4 5 6 7 8 9 10 11
0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025
12 13
0.025 0.025
I hope this helps,
John
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