Operation Manual

Chapter 13: Inferential Statistics and Distributions 249
c
2
pdf(
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:
c
2
pdf(x,df)
c
2
cdf(
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)
Note: For this
example,
Xmin = 0
Xmax = 30
Ymin =
L.02
Ymax = .132
fx
1
 df 2
--------------------
1/2
df/2
x
df 21–
e
x/2–
x 0,=