HP 39g Graphing Calculator - Manual (Page 135)

Two-Proportion Z-Interval
Menu name Z-INT: PI -P2
This option uses the Normal Z-distribution to calculate a
confidence interval for the difference between the proportions
of successes in two populations.
Inputs The inputs are:
Field name Definition
I'l Sample 1 success count.
12
Sample 2 success count.
nl Sample 1 size.
n
2
Sample 2 size.
C Confidence level.
Results The results are:
Result Description
Critical Z Critical value for Z.
ATtMin
Lower bound for the difference between
the proportions of successes.
An Max Upper bound for the difference between the
proportions of successes.
Inference aplet 9-19