Statistics definitions

Question 1

Descriptive statistics

Answer 1

when data is summarised and presented

Question 2

Inferential statistics

Answer 2

When statisicians try to predict or forecast based on responses from a small group

Question 3

Explanatory variable

Answer 3

Variable whose effect on response we study (independent)

Question 4

Response variable

Answer 4

Variable whose changes we wish to study (dependent)

Question 5

Data set

Answer 5

all observations of a particular variable for the elements of the sample, a set of facts or values

Question 6

Categorical Data

Answer 6

Questions that cannot be answered with numbers, qualitative

Question 7

Numerical Data

Answer 7

Questions that provide numerical data, quantitative

Question 8

Ordinal Data

Answer 8

Categorical data that can be ordered ex: grades (H1,H2)

Question 9

Nominal Data

Answer 9

Categorical data that cannot be ordered(Hair colour)

Question 10

Continuous Data

Answer 10

Numerical Data that can be one of an infinite number of values (EX: Rainfall measurements)

Question 11

Discrete Data

Answer 11

Numbers or measurements that can only have certain values (EX: shoes size)

Question 12

Univariate data

Answer 12

data with one value

Question 13

Bi variate data

Answer 13

data with two paired values

Question 14

Observational studies

Answer 14

Researchers collects information but does not influence events, includes case control studies

Question 15

A designed experiment

Answer 15

Researchers apply some treatment to a group then observe the effect it has on them, a control group can be used

Question 16

Experiment

Answer 16

A controlled study in which the researcher understands cause- and effect relationships

Question 17

population

Answer 17

complete set of data under consideration

Question 18

census

Answer 18

The collection of data of the whole population

Question 19

sample

Answer 19

A selected small group from the population

Question 20

Statistical interference

Answer 20

Conclusions drawn from a sample are applied to the whole population

Question 21

Parameter

Answer 21

A number that describes a population characteristic

Question 22

Bias

Answer 22

Anything that distorts the data so it will not give a representative sample

Question 23

Causes of bias

Answer 23

Too small sample
Low response rates
Error in recording data
Failing to identify correct population

Question 24

Name five sampling methods

Answer 24

simple random sample
Stratified random sampling
Systematic Sampling
Quota Sampling
Cluster Sampling

Question 25

Simple random sample

Answer 25

Sample size is selected in such a way that every possible sample of size n from the population has an equal chance of being selected (lottery)

Question 26

Stratified random smaple

Answer 26

Population is divided into subgroups or strata with subjects in each group sharing a characteristic (ex:age) A simple random sample is selected from each startum. Number taken frome ach group is proportional to the size of the stratum rlative to the population

Question 27

Systematic Sampling

Answer 27

Constant skip method. One person is selected at random then every kth name forwards/backwards is selected. K is decided by the size of the population divided by the sample size needed

Question 28

Cluster Sampling

Answer 28

Population divided into clusters (subgroups) then a simple random sample of clusters is selected and all members in each chosen cluster are surveyed

Question 29

Quota Sampling

Answer 29

Dividing population into groups of criteria and a quota of subjects are interviewed from each group but interviewer chooses subjects for convenience

Question 30

What are some ethical issues of clinical trials

Answer 30

Experimental techniques can be healing or harmful Benefits of trials go to future patients not subjects In control trials if a treatment works is in ethical not to give it to the control group

Question 31

What are important when collecting data from anybody- ethics

Answer 31

Informed consent and confidentiality

Question 32

What are the main survey methods- give one advantage and disadvantages of each (not on brainscape but do know this)

Answer 32

``` Face to face interview Telephone interview Postal questionnaire Online questionnaire Observation ```

Question 33

Questionnaire

Answer 33

Set of questions designed to obtain data from a population

Question 34

What makes a good questionnaire

Answer 34

Provides instructions or example of how to complete starts with simple questions be as brief as possible to be answered quite quick Clear about who should complete it

Question 35

What makes good questionnaire questions

Answer 35

``` Clear simple language Relevant to survey Not be open ended- difficult to analyse Not cause offense Provide tick boxes, yes or no answer or number answer ```

Question 36

Symmetric distribution

Answer 36

Values smaller and larger than the midpoint are mirror images of each other

Question 37

Negatively skewed distribtuion

Answer 37

Data is skewed left, mean < median

Question 38

Positively skewed distribution

Answer 38

Data is skewed right mean> median

Question 39

Correlation

Answer 39

Measures strength of the linear association between two quantitative variables

Question 40

outlier

Answer 40

An individual value that fall outside the overall pattern

Question 41

Correlation coefficent

Answer 41

Measure of strength of the linear relationship between two sets of data. Value is between -1 and 1

Question 42

Line of best fit/regression line

Answer 42

Line that describes the relationship between the two variables. Straight line that best fits the data