Unit 1 - Introduction to Statistics

individual

object or subject described in a set of data

variable

attribute that can take different values for different individuals

categorical variable

assigns labels that places each individual into a category

quantitative variable

takes # values that are quantities - can be counts or measurements

discrete variables

result from counting something - is a fixed set

continuous variables

result from measuring something - any values

distribution

pattern of variation- tells what values the variable takes and how often it takes those values

mean

sum of all the data values divided by the number of values present

how do you find the median with an odd number of values?

Q1

median of the first half of the ordered data set

Q3

median of the second half of the ordered data set

range

sing value, the difference between the max and the min (max - min)

IQR

distance between Q3 - Q1

standard deviation

typical distance that each value is away from the mean

method 1 for determining outliers

1.5x IQR below the first quartile or more than 1.5x IQR above the third quartile

method 2 for determining outliers

value located 2 or more standard deviations above, or below the mean

statistic

a number that describes some characteristic of a sample

parameter

a number that describes some characteristic of a population

resistant

a statistical measure is resistant if it isn’t sensitive to extreme values