EXAM REVISION

Question 1

Categorical Nominal

Answer 1

a variable that can be measured in more than two categories that arent in any particular order. eg something can be green, blue, or purple.

Question 2

What are the types of variables?

Answer 2

Continuous - continuous scale in which every value is possible eg. 5.14

Categorical - restricted to one set of categories eg. blue

Discrete - counted on counting/whole numbers (number of children in a family)

Question 3

Continuous variable

Answer 3

measured in a continuous scale in which every value is possible eg. 5.14

Question 4

Categorical variable

Answer 4

restricted to one set of categories eg. green or heads

Question 5

Categorical binary

Answer 5

a variable that can only be one of the two categories that it is measured in. eg. you can only be a smoker or non smoker.

Question 6

Categorical Ordinal

Answer 6

a variable that can be measured in more than two categories that ARE in a particular order. eg. pain tolerance from 1-10

Question 7

what is the difference between categorial ordinal and categorical nominal?

Answer 7

ordinal is in a particular ranking, whereas nominal in just any order of variable categories that the thing can be. eg. level of pain is ordinal, blood type is nominal.

Question 8

discrete variable

Answer 8

a variable that can be counted on counting/whole numbers (number of children in a family)

Question 9

difference between raito and proportion

Answer 9

ratio is one number compared to another

proportion is one number compared to the whole population

Question 10

Rate

Answer 10

Like a ratio for things with different units eg new cases per day.

Question 11

two main types of studies

Answer 11

descriptive or analytic

Question 12

descriptive study

Answer 12

surverys which aim to describe things eg. characteristics, attitiudes.

uses sample from pop. of interest

Question 13

analytic study

Answer 13

aims to test a hypothesis eg. causes, effects, methods of prevention

Question 14

experimental study

Answer 14

a type of analytic study in which the conditions are manipulated by the researcher (interveneing into the natural process).

Aims to control all other factors to isolate the effects of the intervention

Question 15

observational study

Answer 15

a type of analytic study in which the researcher does not intervene. they just observe what is happening and collect data

Question 16

cohort study

Answer 16

type of analytic observational study in which participants are selected for the demographic they’re in BEFORE they’ve gotten the disease and then oberved over time.

Question 17

case control study

Answer 17

type of analytic observational study in which participants are selected BECAUSE they have the disease
A group without the disease is used as the control.

Question 18

stratified sampling

Answer 18

when population is comprised of several groups of similar individuals. find the stratums and take an equal (or proportional) amount from each stratum (via random sample)

Question 19

probability sampling

Answer 19

every member is selected at random. each member of the population has an equal chance of being selected.

eg. cluster, stratified, simple random sampling

Question 20

how to find the sd of probability distribution

Answer 20

∑ x2 times P(x) - m2

1. make x2 column
2. times the x2 column by the p(x) column
3. add all those numbers together
4. get that total and minus it by m2
5. find the square root of that number

Question 21

Cluster sampling

Answer 21

what the pop. is grouped into natural clusters (households) and an amout of hosueholds are selected randomly

two stage - households are randomly selected, and then from within those households, individuals are randomly selected.

Question 22

Sensitivity

Answer 22

the ability of a test to correctly identify patients WITH a disease

Question 23

Specificity

Answer 23

the ability of a test to correctly identify people WITHOUT the disease

Question 24

what are the four factors of binomial distribution?

Answer 24

• fixed number of trials
• each trial must have the same two possible outcomes
• the trials must be independant
• the propabability of success must be the same in each trial

Question 25

how to calculate relative risk?

Answer 25

a/a+b
_____
c/c+d

Question 26

how to calcultate odds ratio?

Answer 26

AxD
___
BxC

Question 27

pr(A|B)

Answer 27

pr(a&b)
______
pr(b)

Question 28

what are prevalence and incidence

Answer 28

Measures of prevalence relate to existing cases of disease

Measure of incidence refer to new cases of disease