Term | Definition |
Statistics | the sciences of collecting, analyzing, drawing conclusions from data |
Descriptive statistics | the methods of organizing and summarizing data |
inferential statistics | involves making generalizations from a sample to a population (hypothesis) |
Population | the entire collection of individual objects about which info is desired |
Sample | subset of the population selected for study in some prescribed manner |
Variable | any characteristic who's value may change from one individual to another |
Data | observations on single variable or simultaneously on 2 or more variables |
Percentile | |
Quartile | |
Types of Variables | |
Categorical/Qualitative | identifies basics differentiating characteristics of the population |
Numerical/Quantitative | observations or measurements taken on numerical values |
Discrete | listable set of values. Ex. Usually counts of items |
Continuous | data can take on any values in the domain of the variable, usually measurements |
Univariate | data that describes a single (un)characteristic of the population |
Bivariate | data the describes 2(bi)characteristics of the population |
Multivariate | data that describes more than 2 characteristics of the pop. |
Graphs for categorical data: | |
Bar | Used for categorical data.
- Not touch
- horizontal axis
- comment on which occurred the most/least
often
- bivariate data sets can have
double/segmented bar graph |
Pie graph | categorical data
- to make one proportion x 360 deg.
- using protractor, mark off ea part
- desribe, comment on which occurred the
most/least often |
Graphs for numerical data: | |
Dotplot | - used w/ numerical data (discrete/continuous)
- put dots (or A's) on number line
- can make comparitive dotplots by using the
same axis for mult. groups |
Shapes: | |
Symmetrical | vertically cut in middle, bell shaped curve |
Uniform | every class has equal frequency |
Skewed | one side is longer than the other. Longer tail left or right) |
Bimodal | 2 classes have same freq & separate to others |
How to describe a numerical graph: | |
Center | where middle of data is.
3 types: mean, medican, mode |
Spread | how spread out data is.
3 types: range, standard deviation, IQR |
Shape | overall shape of distribution
symmetrical, uniform, skewed, bimodal |
Unusual occurances | outliers: value that lies away from rest of data (gaps, clusters) |
In context | all answers written in correct form. Full sentences & correct vocab |