HW question 11.10c

HW question 11.10c

by Molly -

Hi Dr. Newman,

I have what I hope will be a quick clarifying question.

For problem 11.10c  on this week’s homework we are asked to use the shortcut in Chapter 11 to find the lower limit of the 95% CI for the proportion with protective antibody levels in untreated children. I interpreted this short cut “rule of 3” to be used for small numerators. This numerator is 224 in the question stem. Am I missing something obvious here?

 

Thanks!

Molly

Re: HW question 11.10c

by Thomas Newman -

The "rule of 3" is for zero numerators only; the rule of 3,5,7,9,10 is for numerators up to 4.

Mathematically, numerators almost equal to denominators have the same problems as very small numerators, so ( as discussed in lecture and examples in the text) these rules can also be used to get lower limits of 95% CI when the numerator is almost = to or = to the denominator.

Happy Veterans Day!

T