## 39 terms · Elementary Statistics Chapter 1-3

### data

consists of information that comes from observations, counts, measurements, or responses

### statistics

how do we organize, analyze, interpret data in order to make decisions

### population

the collection of all outcomes, responses, measurements, or counts that are of interest

### sample

subset of a population

### parameter

numerical description of the population

### statistic

numerical description of the sample

### descriptive statistics

involves the organization, summarization, and display of data

### inferential statistics

involves using a sample to draw conclusions about a population. A basic tool is probability. Making a decision on stats.

### qualitative data

attributes, labels, NON-NUMERICAL entries. (Things which can't be counted like a zip code, social security #, etc would be this)

### quantitative data

numerical measurements, or counts; things that can actually be counted

### levels of measurement

how we look at data side by side

### nominal level of measurement

qualitative only (names, labels)

### ordinal level of measurement

qualitative or quantitative; order, can be ranked, but the differences between the data entries are meaningless

### interval level of measurement

can be ordered; MEANINGFUL differences between data; Zero (0) entry is simply a position on scale, or a placeholder

### ratio level measurement

Like interval, but zero (0) means 0 (inherit zero). A ratio of two data values can be formed so that one data value can be meaningfully expressed as a multiple of another

### Inherit Zero

None; absolutely nothing

### Design a Stat Study: 1st step

Identify the variables of interest

Develop a plan

Collect data

### Design a Stat Study: 4th step

Describe the data

### Design a Stat Study: 5th step

Interpret the data (inferential)

### Design a Stat Study: 6th step

Identify any possible errors

### observational study

researcher observes and measures characteristics of interest of part of a population, but does not change existing conditions

### experiment

a treatment is applied to part of a population and responses are observed

### treatment

what is applied to part of a population, during an experiment

### control group

no treatment is applied, during experiment

### placebo

harmless, unmediated treatment, that is made to look like the real treatment

### simulation

use of a mathematical or physical model to reproduce the conditions of a situation or process

### survey

an investigation of one or more characteristics of a population

### Three Key Elements of a Well Designed Experiment

control, randomization, and replication

### confounding variable

occurs when an experimenter cannot tell the difference between the effects of different factors on a variable

### hawthorne effect

occurs in an experiment when subjects change their behavior simply because they know they are participation in an experiment

### placebo effect

occurs when a subject reacts favorably to a placebo, when they have been given no medicated treatment at all

### blinding

technique where the subject does not know whether he or she is receiving a treatment or a placebo

### double-blind experiment

neither the subject nor the experimenter knows if the subject is receiving a treatment or a placebo

### blocks

groups of subjects with similar characteristics

### randomized block design

divide subjects with similar characteristics into blocks, and then within each block, randomly assign subjects to treatment groups

### matched-pairs design

subjects are paired up according to a similarity

### replication

the repetition of an experiment using a large group of subjects