Texas Instruments TI-84 - Manual (Page 379)

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 =
L
4.5
Xmax = 4.5
Ymin = 0
Ymax = .4
f x
( )
Γ df 1
+
( )/2 [ ]
Γ df 2 ⁄ ( )
--------------------------------- =
1 x
2
/df +
( )
df 1 +
( )/2
–
πdf
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