| A | B |
|---|
| Quantitative variables | measurable quantity |
| Categorical variables | values that are names or labels |
| Univariate data | study that looks at only one variable |
| Bivariate data | study that examines the relationship between two variables |
| population | the total set of observations that can be made |
| sample | set of observations drawn from a population |
| percentiles | values that divide a rank-ordered set of elements into 100 equal parts |
| Quartiles | divide a rank-ordered data set into four equal parts |
| A standard score | indicates how many standard deviations an element is from the mean |
| z = (X - μ) / σ | The formula for calculating a standard score |
| dotplot | made up of dots plotted on a graph |
| bar chart | is made up of columns plotted on a graph |
| Correlation coefficients | measure the strength of association between two variables |
| explanatory variable | cause |
| response | effect |
| Sample survey | A sample survey is a study that obtains data from a subset of a population |
| Experiment | An experiment is a controlled study in which the researcher attempts to understand cause-and-effect relationships. |
| Observational study | Studies that attempts to understand cause-and-effect relationships. |
| Population parameter | the true value of a population attribute |
| Voluntary sample | A sample that is made up of people who self-select into the survey. |
| Convenience sample | A sample that is made up of people who are easy to reach |
| Simple random sampling | objects that are likely to occur. |
| Stratified sampling | population is divided into groups, based on some characteristic. |
| Cluster sampling | every member of the population is assigned to one, and only one, group. |
| Systematic random sampling | create a list of every member of the population. select the first sample element. Then collect every kth element on the list. |
| Undercoverage. | When some members of the population are inadequately represented in the sample |
