Topic 21: Learning About Two Proportions

Minitab Local Macro pp_beta

Using simulation, summarizes distribution of p2-p1 when proportions have independent beta distributions.

TO RUN:

Suppose that the first proportion p1 has a beta curve with numbers 4 and 2, and the second proportion p2 has a beta curve with numbers 3 and 7. To obtain a simulated sample of 1000 values of the difference in proportions d = p2 - p1, type the following command in the Minitab Session Window. Using the 'store' subcommand, the simulated values of p1 and p2 are stored in the Minitab columns 'p1' and 'p2'.

MTB > %pp_beta 4 2 3 7;

SUBC> store 'p1' 'p2'.

Each dot represents up to 3 points

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+---------+---------+---------+---------+---------+-------PDIFF

-1.00 -0.75 -0.50 -0.25 0.00 0.25

Plot p2 * p1