Introduction to Probability · free preview
The Moment Generating Function
Packaging all moments into one function, reading moments off derivatives, and recognizing distributions by their MGFs.
1. One function, every moment
One function, every moment
2. A catalog of MGFs
A catalog of MGFs
3. Existence, uniqueness, and what MGFs are for
Existence, uniqueness, and what MGFs are for
4. What the MGF stores
The r-th derivative of the MGF evaluated at t = 0 equals what?
5. Identifying by table
A random variable has MGF equal to e raised to the quantity 2 times e to the t, minus 2. Which distribution is it?
6. Bernoulli MGF moment
The Bernoulli(p) MGF is 1 - p + p e^t. Its first derivative at t = 0 is e^0 = 1 times p, plus zero. For p = 0.3, what is the mean? Enter a decimal like 0.3.
7. Exponential mean from MGF
The Expo(lambda) MGF is lambda over (lambda minus t). For lambda = 4, M'(0) = lambda squared over lambda squared, or compute directly: what is the mean? Enter a decimal like 0.25.
8. Uniform MGF check
The Uniform(0,1) MGF is (e^t minus 1) over t. Near t = 0 it limits to 1. Its series begins 1 + t/2 + t squared over 6. What is E(X)? Enter a decimal like 0.5.
9. In your own words
In your own words, state the most important definition, theorem or method of this lesson and explain what it says.
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