13–4 Inferential Statistics and Distributions
8250FC~1.DOC TI-83 international English Bob Fedorisko Revised: 10/26/05 1:39 PM Printed: 10/27/05 2:57
PM Page 4 of 36
To obtain a more precise bound on the population mean m of women’s heights,
increase the sample size to 90. Use a sample mean
þ
þþ
þ of 163.8 and sample standard
deviation
Sx of 7.1 calculated from the larger random sample (introduction; page
13.2). This time, use the
Stats (summary statistics) input option.
7. Press … | 8 to display the inferential stat
editor for
TInterval.
Press ~ Í to select Inpt:Stats. The editor
changes so that you can enter summary
statistics as input.
8. Press † 163 Ë 8 Í to store 163.8 to þ
þþ
þ.
Press 7 Ë 1 Í to store 7.1 to Sx.
Press 90 Í to store 90 to n.
9. Press † to move the cursor onto Calculate,
and then press Í to calculate the new 99
ercent confidence interval. The results are
displayed on the home screen.
If the height distribution among a population of women is normally distributed with a
mean
m of 165.1 cm. and a standard deviation σ
σσ
σ of 6.35 cm., what height is exceeded
by only 5 percent of the women (the 95th percentile)?
10. Press ‘ to clear the home screen.
Press y [
DISTR] to display the DISTR
(distributions) menu.
Getting Started: Mean Height of a Population (cont.)
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