User Manual

Chapter 13: Inferential Statistics and Distributions 244
tpdf(x,df)
Note: For this example,
Xmin = L4.5
Xmax = 4.5
Ymin = 0
Ymax = .4
tcdf(
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(
fx()
1
Γ df 2⁄()
--------------------
1/2()
df/2
x
df 21–⁄
e
x/2–
x 0≥,=
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: