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# Excel to Solve Probabilities - Distributions - Degrees of Freedom

I'm having a problem Using Excel to Solve Probabilities - Distributions - Degrees of Freedom.

The question is listed below and the question with any relevant data is attached as an excel spread sheet.

PROBLEM:

Determine the following quantities using Excel:

(a) Find the value of x such that P (t10x ? X) = 0.75, where t10 has a t distribution with 10 degrees of freedom.

(b) Find the value of y such that P (t100x ? X) = 0.75, where t100 has a t distribution with 100 degrees of freedom. How do you explain the difference between this result and the result obtained in part a?

(c) Find the value of z such that z P (Z ? z) = 0.75, where Z is a standard normal random variable. Compare the results with the results obtained in part a and b. How do you explain the difference in the values of x, y, and z?

[PLEASE FIND THE EXCEL SPREAD SHEET WITH THE QUESTION AND ANY RELEVANT DATA ATTACHED]

#### Solution Preview

Please see the attached for explanation and formulas.

a) P (t10x ? X) = 0.75

By using TINV(probability, degrees of freedom) we can get the value of x
TINV(0.75,10) is 0.327558265

b) P (t100x ? ...

#### Solution Summary

The expert uses excel to solve probability, distribution and degrees of freedom.

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