HP 39g Graphing Calculator - Manual (Page 133)

Two-Sample Z-!nterval
Menu name Z^NT: 111- |i2
This option uses the Normal Z-distribution to calculate a
confidence interval for the difference between the means of
two populations, Pi - P
2
> when the population standard
deviations, O] and 02 , are known.
Inputs The inputs are:
Field name Definition
il
Sample 1 mean.
x2
Sample 2 mean.
nl Sample 1 size.
n
2
Sample 2 size.
al Population 1 standard deviation.
o
2
Population 2 standard deviation.
C Confidence level.
Results The results are:
Result Description
Critical Z Critical value for Z.
A p Min Lower bound for pj - P
2
.
ts p Max Upper bound for P[ - P
2
.
Inference aplet 9-17