DATASCI: Chapter 2

Dot plot

one variable scatterplot

Mean

Often called the average, is a way to measure the center of a distribution of data

Population mean

used to represent the average of all observations in the population

Histogram

Binned counts are plotted as bars which resembles a more heavily binned version of the stacked dots. It provides a view of the data density

Mode

Represended by a prominent peak in the distribution. The value with the most occurances in the data set

Standard deviation

Roughly describes how far away the typical observation is from the mean. The square root of the variance, represents the typical deviation of observation from the mean.

Variance

If we square the deviation and then take an average. The average squared distance from the mean

Boxplot

Summarizes a data set using five statistics while also plotting unusual observations

Median

The number in the middle

Interquartile range

total length of the box

First quartile

the 25th percentile (Q1)

Third Quartile

the 75th percentile (Q3)

Whiskers

extending out from the box, attempting to capture the data outside of the box

Outliers

An observation that appears extreme relative to the rest of the data

Robust Statistics

Extreme observations have little effect on their values, moving the most extreme value generally has little influences on these statistics

Contingency table

A table that summarizes data for 2 categorical variables

Row totals

Provide the total counts across each row

Column totals

total counts down each column

Row proportions

computes as the counts divided by their row totals

Column proportions

computes as the count divided by corresponding column total

Stacked box plot

A graphical display of contingency table information

Pie Chart

categorical data in pie form