# HP 48gII User Manual Page 600

Graphing calculator.

Advertisement

The result indicates that a 95% confidence interval has been calculated. The
Critical z value shown in the screen above corresponds to the values ±z
in
⋅σ/√n , X+z
⋅σ/√n ). The values µ
the confidence interval formula (X−z
/2
/2
Min and µ Max are the lower and upper limits of this interval, i.e., µ Min =
X−z
⋅σ/√n, and µ Max = X+z
⋅σ/√n.
/2
/2
Press @GRAPH to see a graphical display of the confidence interval information:
The graph shows the standard normal distribution pdf (probability density
function), the location of the critical points ±z , the mean value (23.2) and
Press @TEXT to
the corresponding interval limits (21.88424 and 24.51576).
return to the previous results screen, and/or press @@@OK@@@ to exit the confidence
interval environment.
The results will be listed in the calculator's display.
Example 2 -- Data from two samples (samples 1 and 2) indicate that x
=
1
57.8 and x
= 60.0. The sample sizes are n
= 45 and n
= 75.
If it is
2
1
2
known that the populations' standard deviations are σ
= 3.2, and σ
= 4.5,
1
2
determine the 90% confidence interval for the difference of the population
means, i.e., µ
- µ
.
1
2
Press ‚Ù—@@@OK@@@to access the confidence interval feature in the
Press ˜@@@OK@@@ to select option 2. Z-INT: µ 1 – µ2..
calculator.
Enter the
following values:
When done, press @@@OK@@@. The results, as text and graph, are shown below:
Page 18-29

Advertisement

Table of Contents

Symbols: 0