# HP 50g User Manual Page 596

Graphing calculator.

Press @HELP to obtain a screen explaining the meaning of the confidence interval
in terms of random numbers generated by a calculator. To scroll down the
resulting screen use the down-arrow key ˜. Press @@@OK@@@ when done with the
help screen. This will return you to the screen shown above.
To calculate the confidence interval, press @@@OK@@@. The result shown in the
calculator is:
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
the confidence interval formula ( X z
/ n , X+z
/ n ). The values
/2
/2
Min and
Max are the lower and upper limits of this interval, i.e.,
Min = X
z
/ n, and
Max = X+z
/ 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 (23.3) and the
corresponding interval limits (21.98424 and 24.61576). Press @TEXT to 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.
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