Basic Definitions & Concepts:
Data: facts/figures from which conclusions can be drawn
Data Set: data that are collected for particular study
Elements: people, objects, events, or other entries
Variable: any characteristic of an element
Population: set of all elements about which we wish to draw conclusions
Census: examination of all population measurements
Sample: subset of the units of a population Population (Param.) & Sample (Stat.)
Population: group of all items of interest and then the Sample: is the set of data drawn from the pop.
Parameter: A descriptive measure of population
Statistic: A descriptive measure of a sample
“A politician is running for office of mayor in a city w/ 25,000 voters. In survey, 48% of the 200 voters that were interviewed say they will vote for her.” Pop: voters, Sample: 200 voters, Parameter/Statistic: Statistic Descriptive vs. Inferential Stats
Descriptive: Organize, Summarize, Simplify, Presentation of data describes data
Inferential: Generalize from sample to pop, Hypothesis testing, Relationship among variables
Make predictions from this Categorical vs. Quantitative Var.
Categ: places individual into a category (Also Ordinal if there is an order in the categ. Nominal if it is a name of something)
Quant: numerical and math operations make sense (Interval if can find interval b/w the data) Shapes of Histograms
Symmetry: draw vertical line in the middle= will be same on both sides
Skew: Long tail on one side (If long on left it is skewed:Pos/Right if long side right then Neg/Left Modality
Unimodal: single peak
Bimodal: two peaks (two obvious peaks)

Finding # Classes & Length of Histogram

and round up for length Stem & Leaf Plot
The value of the leaf unit is the unit of the leaf side, so if it is 1 | 2 = 12% then the leaf unit is 1 (one’s place)
Distribution given S&L: