STATS 107 Outcome One

Population

Population

Person Places or objects in a study

“Who we want to study”

Sample

A smaller of the population that is possible to study

Parameter

The numerical characteristics of the population

Statistic

A number that represents a portion of the sample

Variable

an x or y

Data

actual values of variable

Difference between population and sample

Population is all

sample is specific

Qualitative data

Categorical data

Quantitative data

Numerical answers

Quantitative discrete data

Data that you can count

Quantitative continuous theta

Data that you can measure

simple random sample

a sample of individuals from the population chosen in such a way that every group of individuals has an equaled chance of selection

systematic

select every nth individual from the population

Stratified

splits the available population into small groups in which the same number of subjects are selected from each group

cluster

all members of a certain group are selected

Census

a survey of all individuals in a population

bias

Favors one result over another

variability

how different the answers are

bias is high

changing sampling methods

Variability is high

take larger samples

frequency

the number of times something occurs

relative frequency

frequency divided by total number

cumulative relative frequency

Adding the relative frequency to your stopping point

experiment

A method of applying treatments to a group and recording the data

Observational study

researchers collect data based on what is seen or heard

experiment

Active data collection involving a treatment imposed on the subjects being studied

subject

the participants in the study

treatment

The specific condition being imposed on the subjects the condition can be a combination of factors

explanatory variable (x axis)

the variable that the experimenter is altering by administering the treatment

Response variable (y-axis)

the variable that we are measuring in the subjects

lurking variable

Any variable that could have in effect on the results

placebo

A dummy treatment with no active ingredients

Placebo effect

Often patients will respond to any treatment

control group

One of the two groups should be receiving either a placebo or an existing treatment

random comparative experiment

Subjects are randomly placed in treatment or control group

blind experiment

A study where subjects do not know which treatment they are receiving

Double blind experiment

A study where the subjects and the people administering the treatment do not know who receives each treatment

clinical trial

An experiment testing the effectiveness of a medical treatment on human patients

Stem and Leaf Plots

Best for Discrete or Continuous Data

Line Graph

Best to use with Continuous Data

Histogram

Best to use with large amounts of any quantitative data

Percentile

A number that divides the order

Percentile Formula

x=k(n+1)