Flashcards in Biostats Deck (41):

1

## sensitivity

### TP/(TP+FN)

2

## specificity

### TN/ (TN+FP)

3

## PPV

### TP / (TP+FP)

4

## NPV

### TN / (TN+FN)

5

## incidence vs. prevalence vs. attack rate

###
incidence = # new cases/ # vulnerable

prevalence = #existing cases/population at risk

attack rate = #sick/ #who were exposed

6

## OR

### (a/c)/(b/d) = ad/bc

7

## RR

### (a/(a+b)) / (c/(c+d))

8

## relative risk reduction

### 1 - RR

9

## attributable risk

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

10

## Absolute risk reduction

### difference in risk compared to control

11

## NNT

### 1 / ARR

12

## number needed to harm

### 1 / AR

13

## random error

### reduces the precision in a test

14

## systematic error

### reduces the accuracy of a test

15

## examples of selection bias

### - berkson bias (study only looking at inpatients), loss to follow up, health care worker study

16

## measurement bias

### Hawthorne effect - pts who know they are being studied behave differently than they normally would

17

## positive skew data

###
mean > median > mode

- curve leans to the left (tail goes positive)

18

## negative skew data

###
mean < median < mode

- curve leans to the right (tail goes negative)

19

## type I error (a)

###
- stating that there is an effect or difference when there isn't one

- a is the probability of making a type 1 error, if p <0.05 then there is a less than 5% chance that the data will show something that is not really there

20

## type II error (b)

###
- stating that there is not an effect or difference when one exists

- b is the probability of making a type II error

- 1-b is the statistical power, which is the probability of rejecting the null hypothesis when it is false (aka probability of finding a true relationship)

- increased power and decreased b by increasing sample size, increasing expected effect size and increasing precision of measurement

21

## calculating 95% confidence interval

### - 95% CI = Mean +/- 1.96*SD/sqrt n

22

## t test

### checks differences between the means of 2 groups

23

## ANOVA

### checks differences between means of 3 or more groups

24

## chi-square test

### checks differences between 2 or more percentages or proportions of categorical outcomes (not mean values)

25

## pincer grasp

### 10 months

26

## babinski disappears

### 12 months

27

## points to objects

### 12 months

28

## stranger anxiety

### 6 months

29

## separation anxiety

### 9 months

30

## object permanence

### 9 months

31

## first words

### 10 months

32

## number of cubes they can stack

### age in years x 3

33

## feeds self with fork/spoon

### 20 months

34

## kicks ball

### 2 years

35

## 200 words

### 2 years

36

## 1000 words

### 3 years

37

## line, circle or stick figure

### 4 years

38

## hops on one foot

### 4 years

39

## grooms self/buttons buttons

### 5 years

40

## cooperative play

### 4 years

41