# Elementary Probability and Statistics- Chapter 1

## 31 terms

### individuals

the objects described in a set of data.

### cases

When the objects are people in a set of data

### variable

any characteristic of an individual

### catagorical variable

an individual into one of two or more groups or categories

### quantitative variable

numerical values for which arithmetic operations such as adding and averaging make sense

### distribution

a variable tells us what values it takes and how often it takes these values
of categorical - gives us either the count of the percent of individuals that fall in each category

### exploratory data analysis

examination of data and describe its main features

### bar graph

quickly compares data in column form, the heights can also show percents

### pie chart

shows us the percents or count in relationship to a whole

### stem plot

gives a quick picture of the shape of a distribution while including the actual numerical values in the graph

### splitting stem/ trim

terms to slim down the size of your stem plot. helpful when you have large sets of data

### histogram

breaks the the range of values of a variable into classes and displayus only the count or percent of the observations that fall into each class, no space inbetween each bar

### examining terms for distribution

overall pattern, deviations, shape, center, spread, outlier

### modes

unimodal - one peak
bimodal - two peaks
multimodal- multiple peaks

### time plot

a variable plots each observation against the time at which it was measured

### trend

persistent, long term rise or fall

### time series

measurements of a variable taken at regular intervals over time

### mean

the arithmetic average

### median

midpoint of the data

### quartiles

describes the distribution further
Q1 : 1/4 of the data
Q3 : 3/4 of data

### interquartile range

difference between quartiles
use 1.5 x IQR to solve for any outliers

### five number summary

median, quartials and the min and max number

### box plots

made based off of the 5 number summary
modified - shows outliers

### standard deviation

is zero when there is no spread and gets larger as the increase spreads

### resistance measure

any aspect of a distribution is relatively unaffected by changes in the numerical value of a small proportion of the total number of oberservations no matter how large these changes are

### linear transformations

changes the original variable x into the new variable x(new) given by the euation ***

### density curve

the overall pattern of a distribution, areas underneath give proportions of observations for the distribution

### normal distributions

bell curve, symmetric, unimodal density curves

### z score

how many standard deviations x lies from the distribution mean

### normal quartile plot

a pattern on such a plot that deviates substantially from a staight line indicates that the data are not normal