13-4 Inferential Statistics and Distributions
8313INFE.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:47 PM Printed: 02/19/01 1:38 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 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.
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 percent 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 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.