Biostatistical Concepts

Question 1

Data Exists in What 2 Categories

Answer 1

Numerical Variables
(counts, measurements)

Categorical variables
(classifying, ordinal data)

Question 2

How can data be summarized

Answer 2

tables, graphs, pie charts, component band charts, spot maps, rate maps, line graphs, frequency distributions and histograms, normal distributions

Question 3

The Mean

Answer 3

Most prominent

The sample average

Question 4

The Median

Answer 4

The middle after all the measurements have been put in order according to their value

Question 5

the Mode

Answer 5

Value of the measurement in the sample that occurs most frequently

Question 6

Measures of Validity

Answer 6

Variance, standard deviation, standard error.

Question 7

Random Samples

Answer 7

Process of random sampling is essential to statistical interference. Equal chance of being selected for sample.

Question 8

Confidence Intervals

Answer 8

In order to construct a lower bound and a upper bound are calculated. To create a reasonable bound for the population mean based on info from a sample.

Question 9

The P Value

Answer 9

represents the likelihood that a value for the mean of a random sample from this population

Question 10

Statistical Power

Answer 10

The higher the power the better, power is affected by the sample size and the variance of the individual observation

Question 11

T-tests

Answer 11

Uses a statistic that under the null hypothesis tests whether these two means differ significantly

Question 12

Correlation

Answer 12

Quantifies the degree to which two variables vary together. If variables are independent, then no relationship.

Question 13

Chi-squared tests

Answer 13

Tools for displaying numbers of participants according to two or more factors or variables. Close examination of the table leas to the inevitable question of whether or not there is evidence of an association between exposure and disease

Question 14

Regression

Answer 14

Regression models are vital tools for data analysis and are used extensively:
Linear regression
Logistic Regression
Cox proportional hazards regression

Question 15

Linear regression

Answer 15

The dependent variable needs to be a continuous variable with its frequency distribution being the normal distribution

Question 16

Logistic regression

Answer 16

The dependent variable is derived from the presence or absence of characteristics typically represented by 0 or 1

Question 17

Cox proportional hazards regression

Answer 17

The dependent variable represents the time from a baseline of some type to the occurrence of an event of interest.

Question 18

Kaplan Meier survival curves

Answer 18

i. Display any type of time-to-event data
ii. Proportions range from 1.0 at the outset don to 0.0.
Plot curves with survival time on horizontal axis rather than calendar time

Question 19

The two-sample t test

Answer 19

Specify population variance, the values from normal distribution, and the difference we want to detect.

Question 20

The test comparing two proportions

Answer 20

Population portions must be specified, prudent to complete calculation several times.

Question 21

Meta-analysis

Answer 21

Statistical synthesis of the data from separate but similar studies leading to a quantifiable summary of the pooled results to identify the overall trend.

Question 22

steps for Meta-analysis

Answer 22

1) Formulate the problem and study design
2) Identify relevant studies
3) Excluding poorly conducted studies or those with major methodological flaws
Measuring, combining, and interpreting results