Stats

Question 1

Pmf

Answer 1

Probability mass function

Question 2

Probability mass function

Answer 2

a function that gives the probability that a discrete random variable is exactly equal to some value

Often expressed in piecewise form

Question 3

Bernoulli distribution

Answer 3

the probability distribution of a random variable which takes the value 1 with probability p and the value 0 with probability q=1-p

Question 4

Autoregressive

Answer 4

A statistical model is autoregressive if it predicts future values based on past values

Question 5

Etymologically speaking what does autoregressive mean?

Answer 5

regression on self.

/(Autoregression is just predicting a future outcome of a sequence from the previously observed outcomes of that sequence)

Question 6

Logit is the inverse of

Answer 6

The standard logistic function

Question 7

Logit domain

Answer 7

(0,1)

Question 8

Logit range

Answer 8

(-inf, +inf)

Question 9

Logit is defined as

Answer 9

logit p = ln (p/(1-p)) for p in (0,1)

Question 10

What is the formula for odds?

Answer 10

p/(1-p), where p is the probability that a particular outcome occurs, and 1 - p is the probability that outcome does not occur

Question 11

Logit is also called what?

Answer 11

Log odds

Question 12

Why is logit called log odds?

Answer 12

Because it is defined as the log of odds. Ln (p/(1-p)) for p in (0,1)

Question 13

What is the cumulative distribution function of Exponential(λ)

Answer 13

Question 14

Quantile function is aka

Answer 14

The percentile function

Question 15

What is the quantile function of the normal distribution?

Answer 15

Probit

Question 16

Probit is the inverse of what?

Answer 16

The cumulative distribution function of the normal distribution

Question 17

What is the difference between a pdf and a cumulative distribution function?

Answer 17

a Pdf f of a random variable X yields the “relative likelihood” f(x) that the random variable would yield x. A cdf f of a random variable X yields the probability f(x) that X would yield a value <= x

Question 18

Difference between pdf and pmf?

Answer 18

Pmf is for discrete variables

Pdf is for continuous variables

Question 19

Pdf stands for

Answer 19

Probability density function

Question 20

Pmf stands for

Answer 20

Probability mass function

Question 21

Z score

Answer 21

how many standard deviations a value is from the mean

Question 22

Multiple logistic regression

Answer 22

Logistic regression, except you have multiple possible outcomes instead of one

Question 23

Difference between sigmoid and logistic function?

Answer 23

Sigmoid is just one instance of the logistic function, where L = 1, k = 1, x0 = 0

Question 24

Standard logistic function formula

Answer 24

Question 25

Explanation of each variable in logistic function

Answer 25