User's Manual

Inferential Statistics and Distributions 13-31
8313INFE.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:47 PM Printed: 02/19/01 1:38 PM
Page 31 of 36
tcdf( computes the Student-
t
distribution probability
between
lowerbound
and
upperbound
for the specified
df
(degrees of freedom), which must be > 0.
tcdf(
lowerbound
,
upperbound
,
df
)
c
2
pdf( computes the probability density function (pdf) for
the
c
2
(chi-square) distribution at a specified
x
value.
df
(degrees of freedom) must be an integer > 0. To plot the
c
2
distribution, paste
c
2
pdf( to the
Y=
editor. The probability
density function (pdf) is:
fx
df
xex
df df x
()
()
(1/2)=≥
−−
1
2
0
221 2
Γ
/
,
// /
c
2
pdf(
x
,
df
)
Note:
For this example,
Xmin = 0
Xmax = 30
Ymin =
L
.02
Ymax = .132
c
2
cdf( computes the
c
2
(chi-square) distribution probability
between
lowerbound
and
upperbound
for the specified
df
(degrees of freedom), which must be an integer > 0.
c
2
cdf(
lowerbound
,
upperbound
,
df
)
tcdf(
c
2
pdf(
c
2
cdf(