11-16 Inference aplet
Results The results are:
Two-Sample Z-Interval
Menu name Z-INT: μ1– μ2
This option uses the Normal Z-distribution to calculate a 
confidence interval for the difference between the means 
of two populations, μ
1
– μ
2
, when the population standard 
deviations, σ
1
 and σ
2
, are known. 
Inputs The inputs are:
Results The results are:
Result Description 
Critical Z Critical value for Z.
μ min Lower bound for μ.
μ max Upper bound for μ.
Field 
name
Definition
Sample 1 mean.
Sample 2 mean.
n1 Sample 1 size.
n2 Sample 2 size.
σ1 Population 1 standard deviation.
σ2 Population 2 standard deviation.
C Confidence level.
x1
x2
Result Description
Critical Z Critical value for Z.
 μ Min
Lower bound for μ
1
 – μ
2
.
 μ Max
Upper bound for μ
1
 – μ
2
.
Δ
Δ
HP 39gs English.book  Page 16  Wednesday, December 7, 2005  11:24 PM