Chapter 13: Inferential Statistics and Distributions 376
tpdf(
tpdf(tpdf(
tpdf(
tpdf( computes the probability density function (pdf) for the Student-t distribution at a
specified x value. df (degrees of freedom) must be >0. To plot the Student-t distribution,
paste tpdf( to the Y= editor. The probability density function (pdf) is:
tpdf(x,df)
tcdf(
tcdf(tcdf(
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)
Note: For this example,
Xmin = L4.5
Xmax = 4.5
Ymin = 0
Ymax = .4
f
x() Γdf 1+()/2[]
Γdf 2⁄()
---------------------------------= 1x2/df+()
df 1+()/2–
πdf
-------------------------------------------------