Flashcards in Biostatistics Deck (31)

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1

## Continuous data

###
data with numeric values

-age, weight, height, A1c, etc

2

## Categorical data

###
data with categorical values

-gender, race, exposure/disease status

3

## Normal Distribution

### symmetrical around the mean, bell shaped

4

## normal distribution: -1σ to +1σ

### 68%

5

## normal distribution: -2σ to +2σ

### 95%

6

## normal distribution: -3σ to +3σ

### 99.7%

7

## Bimodal distribution

### suggestive of two different population

8

## right skewed distribution

### mode

9

## left skewed distribution

### mean>median>mode

10

## Descriptive statistics for continuous data

###
measures of central tendency: mean, median, mode

measures of dispersion: variance, SD

graphic representation: histogram, box plot, line graph

11

## Descriptive statistics for categorical data

###
frequency

proportion: rate, ration, prevalence, incidence rate, relative risk, odds ratio, sensitivity, specificity

graphic: pie chart, bar graph

12

## Measures of central tendency

###
Mean: sum of values/total # of values

Median: value in middle of a ranked data

Mode: value that occurs most often

13

## Measures of dispersion

###
Variance: (sum of square of deviance from mean) divided by (total number of variable - 1)

SD: square root of variance

Standard error of mean: SD / (square root of total number of values)

14

## Inferential statistics

### to make an inference for a population group from a sample group

15

## Population group

### complete collection to be studied

16

## Sample group

### Part of the population of interest selected for study

17

## Goal of Statistical Hypothesis Testing (SHT)

### make decisions about a population from a sample

18

## Procedure of SHT

###
1. state null hypothesis

2. state alternative hypothesis

3 select level of significance

4. collect and summarize the sample data into a statistic

5. refer to a criterion for evaluating the sample evidence producing p-value

6. make a decision to reject/retrain null hypothesis based on p-value

19

## Significance level

### standard defined by probability of rejecting a true null hypothesis (false positive)

20

## P value

### quantifies how consistent your sample statistics are with the null hypothesis

21

## high p value

### same results are consistent with null hypothesis that is true

22

## low p value

### your sample results are not consistent with a null hypothesis which is true

23

## Type I error

### false positive

24

## Type II error

### false negative

25

## Power

### true positive

26

## confidence interval

###
quantifies the uncertainty in the estimates

the narrower interval implies higher precision with less variability

the wider interval implies lower precision with increased coverage

27

## If CI contains a null value

### it fails to reject null hypothesis

28

## If CI does not contain null value

### it rejects the null hypothesis

29

## Student's t-test

### compares means of 2 independent groups

30