HP 39g Graphing Calculator - Manual (Page 132)

Confidence intervals
The confidence interval calculations that the HP 39G/40G can
perform are based on the Normal Z-distribution or Student’s
t-distribution.
One-Sample Z-Interval
Menu name Z-INT: 1 |i
This option uses the Normal Z-distribution to calculate a
confidence interval for p, the true mean of a population, when
the true population standard deviation, o, is known.
Inputs The inputs are:
Field name Definition
1
Sample mean.
a Population standard deviation.
n Sample size.
c Confidence level.
Results The results are:
Result Description
Critical Z Critical value for Z.
\i min Lower bound for p.
\x max Upper bound for p.
9-16 Inference aplet