HP 49g Graphing Calculator - Manual (Page 183)

Confidence intervals
The confidence interval calculations that the HP 49G can perform are
based on the Normal Z-distribution or Student’s t-distribution.
One-Sample Z-Interval
Menu name: Z-INT: 1 |l
This option uses the Nonnal Z-distribution to calculate a confidence
interval for p, the true mean of a population, when the true population
standard deviation, a, is known.
Inputs
X
a
n
C
Results
Critical Z
p min
p max
Sample mean.
Population standard deviation.
Sample size.
Confidence level.
Critical value for Z.
Lower bomid for p.
Upper boimd for p.
Two-Sample Z-Interval
Menu name: Z-INT: pi- p2
This option uses the Normal Z-distribution to calculate a confidence
interval for the difference in the means of two populations, pj and P
2,
when the population standard deviations, and 02 are known.
Inputs
X
1 Sample 1 mean.
x2 Sample 2 mean.
0l Population 1 standard deviation.
02 Population 2 standard deviation.
nl Sample 1 size.
n2 Sample 2 size.
C Confidence level.
Using statistics Page 9-15