In testing the hypotheses

Question

In testing the hypotheses

H0: p1 – p2 = 0 H1: p1 – p2 ‡ 0

you have the following statistics:

n1 = 200, x1 = 80, n2 = 400, x2 = 140

What is the value of the confidence interval estimator at the 95% level for the difference between the two population proportions?

–0.05 ± 0.0692

0.05 ± 0.0035

0.05 ± 0.0692

0.05 ± 0.0824

Answer 1

Ok, practical Use Case..

Marketing (A/B testing)

You run two campaigns:

1. Version A converts at 40%
2. Version B converts at 35%

Looks better, right? But your interval says: “This could actually be worse… or better… we don’t know yet.”

What do you do reporting this??

From the trenches (30 years).

This is what happens

It went up, ship it

They see:

1. 35% → 40%

And say: “That’s a 5% lift. Roll it out.” I guarantee it.

No stats. No interval. Just vibes. How do you sway them?

that's the real value here