Biostatistics

Question 1

Statistics

Answer 1

• Study of how information should be reflected on

- Given guidance for action in a particular situation involving uncertainty

Question 2

Biostatistics

Answer 2

• Application of statistical methods to the medical and health sciences
• Includes epidemiology

Question 3

Main Goals

Answer 3

1. To obtain descriptive information about the population from which the sample is drawn
2. To test research hypothesis about population

Question 4

Population

Answer 4

Any large collection of objects or individuals about which information is desired

Question 5

Parameter

Answer 5

Summary number that describes the entire POPULATION, averages or percentages for example

Question 6

Sample

Answer 6

Representative group drawn from the population

Question 7

Statistic

Answer 7

Any summary number that describes the SAMPLE, like an average or percentage

Question 8

Population v.s. Sample

Answer 8

• Population: Contains all members of a specified group

- Sample: part/subset of population, ALWAYS less than entire population

Question 9

Why sample?

Answer 9

• Economic advantage
• Time factor
• Very large populations
• Inaccessible populations
• Destructive nature of the observation

Question 10

Types of Data

Answer 10

• Binary (discrete)
• Categorical (discrete)
• Continuous

Question 11

Binary Data Examples

Answer 11

• Yes/No
• Success/failure
• Alive/dead

Question 12

Categorical Data

Answer 12

• Nominal: unordered/qualitative
• Gender, race, martial status, education, etc.
• Ordinal/Hierarchial: scales or statuses for comparison

Question 13

Continuous

Answer 13

• Age, height, weight, temperature, distance, etc.
• Measured on continuum or scale
• Ratio accomadates a value of zero
• Distance between each unit has the same meaning or measurement
• Continuous data can have almost ANY numerical value and can be meaningful at any interval

Question 14

Mean

Answer 14

• Arithmetic average
• Measure of central tendency for continuous variables
• Affected by outliers

Question 15

Medium

Answer 15

• Middle value of an ordered data distribution (50th percentile)
• Measure of central tendency for continuous variables
• NOT affected by outliers

Question 16

Mode

Answer 16

• Most frequent value
• Not affected by outliers
• Measure of central tendency

Question 17

Variability

Answer 17

• Describes data dispersion

- Helps define whether study groups are drawn from different populations

Question 18

Range

Answer 18

• Measure of variability

- Difference between max and min values

Question 19

Quartiles

Answer 19

• Measure of variability

- Q1 and Q3 values separate the bottom and top 25% of the data

Question 20

Standard Deviation

Answer 20

• SD
• Measure to quantify dispersion/variation of a set of values
• Quantified the difference of individual observation from teh mean of the set values

Question 21

Standard Error of the Mean

Answer 21

• SEM

- Standard deviation of the sampling distribution of the mean

Question 22

SEM v.s. SD

Answer 22

• SEM describes how precise the mean of the sample is compared to the true mean of the population
• Sample size increases, SEM decreases
• SD may be more or less as sample size increases depending on the dispersion of the additional data added to the sample