Chapter 3 PMF

Question 1

What is a Probability Mass Function (PMF)?

Answer 1

a map of each value to its probability.

Question 2

What is the class size paradox?

Answer 2

The process of getting biased results due to more observations of large population. (ex. larger class size are observed more, so observations must be normalized)

Question 3

Give the three sentaxs for selecting serises data from a dataframe?

Answer 3

df[‘a’] (simple indexing to select a column)

df. loc[‘a’] (loc attricutre to select row by label)
df. iloc[‘0’] (loc attribute to select row by int position)

Question 4

Calculate a Pmf from this list

[1, 2, 2, 3, 5]

Answer 4

{1: 0.2, 2: 0.4, 3: 0.2, 5: 0.2}

Question 5

Mathmatical definition for mean from a Pmf?

Answer 5

Where xi are the unique values and pi is the probability of that value from the Pmf