Calculator User Manual

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

x()

Γ df 1+()/2[]

Γ df 2⁄()

---------------------------------=

1 x

/df+()

df 1+()/2–

πdf

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