Terminology

Question 1

Descriptive studies

Answer 1

Record activities, observations or events
Rare to provide info to evaluate new treatments

Eg case reports, case studies, population studies/cross-sectional studies

Question 2

Case series

Answer 2

Tracks patients with a known exposure or similar treatments, or examines their medical records for exposure and outcome

Question 3

Cross-sectional studies

Answer 3

Information about a population at a slice in time

Question 4

Explanatory studies

Answer 4

Seek to find info about the causes of illness or the effectiveness of treatments

Question 5

Observational studies

Answer 5

Studies of the course of disease and health events, then the results are used to reach conclusions

Types:
Identify individuals known to have a disease or problem, then looking for factors in the past that might have led to the problem
Dealing with individuals who don’t have a problem, but following them over time to study characteristics that might be related to development of a disease or problem.

Question 6

Case control study

Answer 6

Individuals who ar known to have a disease or problem of interest and compares to others who aren’t affected

Question 7

Cohort study

Answer 7

Selecting a starting point and collecting information as you go
Essentially a follow up study
Look at the causes of disease - identifying individuals with some sort of exposure and following them over time to see what happens to them
Provides info about the course and prognosis of diseases
Nature of group influences generalizability

Question 8

Interventional studies

Answer 8

Specifically examine the effect that some intervention might have on patients

Eg social support, New med, new procedure to treat illness

Question 9

Evidence level rankings

Answer 9

1 or A:RCT
II-I: CT but not random
II-2 or B: cohort. Or case-control studies
II-3. Or C: case series
III or D: expert opinion or descriptive studies

Question 10

Nominal data

Answer 10

Categorical. Data
Given names
No level of severity, just different grouping. Eg blood type

Question 11

Ordinal data

Answer 11

Categorical
Describe a progression. Of something
Observation put in order
Eg cancer stage

Question 12

Binary data

Answer 12

Yes/no

Dead//alive

Question 13

Continuous variables

Answer 13

Any value in a range

Height, weight, etc

Question 14

Discrete data

Answer 14

Can only take certain values

Doses given,, completed weeks of gestation

Question 15

Qualitative

Answer 15

Descriptions

Describe qualities of the. Information

Question 16

Quantitative.

Answer 16

Can. Be measured with a numerical value.

Question 17

Mode

Answer 17

Most common value within a group

Question 18

Standard deviation

Answer 18

Spread of data
Mean of the mean
Tells how tightly all the various examples are clustered around the mean in a set of data

Question 19

Confidence interval

Answer 19

Upper and lower values that will include 95% of data from a sample

Question 20

Probability distribution

Answer 20

Way of showing the chances that any value will be found in a population
Eg normal distribution

Question 21

Null hypothesis

Answer 21

No difference between two interventions

Question 22

Alternative hypothesis

Answer 22

Real difference in the effectiveness of interventions

Question 23

Statistical significance

Answer 23

%5% chance (1:20) that the difference found between two interventions in the study are due to random chance
95% certainty that the difference is real

Question 24

P-value

Answer 24

Probability that the alternative hypothesis is correct

Question 25

Chi squared probability test

Answer 25

The sum of the squared difference between observed and expected data, divided by the expected data in all possible categories
Chi Squared = (o-e)^2/e

Used with independent groups

Question 26

Paired t-test

Answer 26

Used to determine whether the mean difference between two sets of observations is zero OR
Used to compare 2 population means where you have two samples in which observations in one sample can be paired with observations in the other sample
Used to determine if there is a sig diff between mean in two groups
Need the mean difference, standard deviation of each group, and the number of data values of each group

Used in case-control studies or repeats-measures designs
Eg before and after observations on the same subjects
A comparison of 2 different methods of measurement or two different treatments where the measurement/treatments are applied to the same subjects

Question 27

Absolute risk

Answer 27

Probability that a certain event will occur in a specified population

Question 28

Absolute risk difference/risk reduction

Answer 28

Difference in risk for an event or outcome between an exposed population and an unexposed population

Question 29

Relative risk

Answer 29

Used in RCT and cohort studies

Ratio of two risks (or probabilities), usually the risk of an event or disease in an exposed group and the risk in an unexposed group

Question 30

Odds ratio

Answer 30

Ratio of two mutually-exclusive events

Eg have pre-eclampsia, do not have pre-eclampsia

Question 31

Type 1 error

Answer 31

Rejecting the null hypothesis when it is true

Question 32

Type II error

Answer 32

Not rejecting a null hypothesis when the alternative hypothesis is the true state of nature

-usually when sample size too small

Question 33

Unpaired t test

Answer 33

Compares two independent samples drawn from the same population

Mann-Whitney U test

Question 34

F test

Answer 34

One way analysis of variance using total sum of squares

Compare three or more sets of observations on a single sample

Question 35

Pearson’s r

Answer 35

Product moment correlation coefficient

Assesses the strength of the the straight line association between two continuous variables

Question 36

Multiple regression by least squares method

Answer 36

Describes the numerical relation between a dependent variable and several predictor variables (covariates)

Question 37

Incidence

Answer 37

Number of new cases of a condition or disease in a given population over a given time