Flashcards in Statistics Deck (13):

1

## Variance =

### Variance = SD squared

2

## Standard Error =

### SD / Square root (n)

3

## Positive skew - highest to lowest mean median mode

### Positive skew, Mean > Median > Mode

4

## Negative skew

###
Mode > Median > Mean.

The skew pulls the mean and median in its direction.

The mode is the least changed by skew.

5

## Normal distribution

### Mean = Median = Mode

6

## Type 1 error

###
rejecting a correct null hypothesis,

false positive error

7

## Type 2 error

### not rejecting an incorrect null hypothesis.

8

## Attributable risk

###
AR = a/(a+b) - c/(c+d)

AR = Prevalence of disease in the exposed group - prevalence of the disease in the non-exposed

9

## Absolute risk reducion

###
The reverse of the attributable risk.

ARR = c/(c+d) - a/(a+b)

Percentage of people who got the disease with no intervention - the percentage of people who got the disease after the treatment.

10

## Number needed to treat

###
NNT = 1/ARR

Pirates love treats ARR!

11

## Number needed to harm

###
NNR = 1/AR

hARm

1/AR

12

## LR+, positive likelihood ratio

###
LR+ = sensitivity/1-specificity = true positive % / false positive %

13