Chapter 1 Flashcards
Data
A collection of observations
Statistics
The science of planning studies and experiments, obtaining data, and then organizing, summarizing, presenting, analyzing, interpreting, and
drawing conclusions based on the data
Population
All of the individuals or items to be studied
Cencus
The collection of data from every member of the population
Sample
A subcollection of members selected from a population
Things to consider
- Context of the data
- Source of the data
- Sampling method
- Conclusions
- Practical implications
Correlation is not
Causation
Parameter
A numerical measurement describing some characteristic of a population
Statistic
A numerical measurement describing some characteristic of a sample
Quantitative data
Numerical data representing counts or measures
Categorical data
Qualitative data representing names or labels
Discrete data
The number of possible values is either a finite
number or a “countable” number. (That is, the number of possible values is 0 or 1 or 2, and so on.)
Continuous (numerical) data
Infinitely many possible values that correspond to some continuous scale that covers a range of values with-out gaps, interruptions, or jumps.
Nominal level of measurement
Names, labels, or categories only; cannot be arranged in low to high, grades, eye color
Ordinal level of measurement
Can be arranged in some order, but differences (obtained by subtraction) between data values
either cannot be determined or are meaningless, ranks
Interval level of measurement
Can be arranged in order, and differences (obtained by subtraction) between data values are meaningful; no natural zeros, temperatures, years
Ratio level of measurement
Can be arranged in order, and differences (obtained by subtraction) between data values are meaningful with natural zeros; distances, prices
Ways to misuse statistics
Lie, bad graphs, bad samples, bias, Correlation and Causality, reported results, Misused Percentage, Loaded Questions, poor wording
Voluntary response sample
the respondents themselves decide whether to be included; stronger opinionated people mostly
Correlation and Causality
Statistical association does not mean one variable causes the other
Observational study
Observe and measure specific characteristics,
but we don’t attempt to modify the subjects being studied
Experiment
Apply some treatment and then proceed to observe its effects on the subjects
Simple random sample
A specific number of subjects is selected in such a way that every possible sample of the same size n has the same chance of being chosen
Random sample
members from the population are selected in such a way that each individual member in the population has an equal chance of being selected
Probability sample
Selecting members from a population in
such a way that each member of the population has a known (but not necessarily the same) chance of being selected
