EXCEL FUNCTION

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• EXCEL FUNCTION
• T Distribution

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T distribution function

• There are two Excel functions for T Distribution
• TDIST given t-value, it returns probability for
  t distribution
• TINV given probability, it returns t-value as
  function of

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T DIST

• TDIST(t,df,tails)
• t the numeric value at which to evaluate the
  distribution.
• df an integer indicating the number of degrees
  of freedom.
• tails specifies the number of distribution tails
  to return.
• If tails 1, TDIST returns the one-tailed
  distribution.
• If tails 2, TDIST returns the two-tailed
  distribution.

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T DIST

• If tails 1, TDIST is calculated as TDIST P(
  Xgtt )
• If tails 2, TDIST is calculated as TDIST
  P(X gt t) P(X gt t) P(X lt -t).
• Since t lt 0 is not allowed, to use TDIST when t lt
  0,
• If tails 1 use TDIST(-t,df,1) 1
  TDIST(t,df,1) P(X gt -t)
• If tails 2 use TDIST(-t,df,2)

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T INV

• TINV(probability,df)
• probability the probability associated with the
  two-tailed Student's t-distribution.
• df the number of degrees of freedom with which
  to characterize the distribution.

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T INV

• TINV returns that value t,
• such that P(X gt t) probability
• A one-tailed t-value can be returned by replacing
  probability with 2probability.