Statistics Unit 2 Checkpoint 1

Numerical summaries

category counts and percentages

Producing Data

choosing a sample and collecting data from it

Multimodal

distributions with more than two modes

Probability

likelihood that a particular event will occur

Outlier

observations that fall outside the overall pattern

Unimodal

one peak

Data

pieces of information about individuals organized into variables

Quantitative Variable

takes numerical values for which it makes sense to find an average

Distribution of a Variable

tells us what values it takes and how often it takes these values

Mean

the average value of a group of numbers

deviation

the difference between an individual score and the average score for the distribution

Median

the middle score in a distribution; half the scores are above it and half are below it

Mode

the most frequently occurring score(s) in a distribution

Symmetry and skewness

the shape of the data

Bimodal

two peaks

Inference

A conclusion reached on the basis of evidence and reasoning

Individual

A particular person/object

Graphical display

A visual representation of a distribution.

Shape

Describes the different types of graphs

Mean or median sensative to outliers?

Mean

Modality

Number of peaks (modes) the distribution has

Center

The midpoint of a data set where the middle values are concentrated Half the observations take larger values and half take smaller In picture: 70 is center.

skewed right distribution

The peak of the data is to the left side of the graph. There are only a few data points to the right side of the graph. Most observations small while only some are larger

Skewed Left Distributions

The peak of the data is to the right side of the graph. There are only a few data points to the left side of the graph. Most observations large while only some are smaller

Spread

Range covered by the data (range=max+min)

Symmetric Graph

Same on both sides Mean = median

Find shape, center, spread, and outliers of the picture

Shape- skewed right Center- around 34/35 (half are below 34) Spread- data ranges from 20 to 80. range is 60 (80-20=60) Outliers- 2 possible outliers to far right and maybe 3 round 62

Exploratory Data Analysis (EDA)

Summarizing collected data

Distribution

a listing or function showing all the possible values (or intervals) of the data and how often they occur

Variable

a particular characteristic of the individual

Categorical Variable

a variable that names categories (whether with words or numerals)