Chapter 3 Flashcards
descriptive statistics
methods that summarize the characteristics of data
inferential statistics
use sample statistics to make generalizations about a population
rounding rule
round to one extra decimal place that is present in the original data set
measure of center
represents the center/middle of the data
mean
add all data values and divide by amount of data values
x̅
mean found using sample data
μ
mean found using population data
median
middle value of the data set
x~
median symbol
mode
data value with the highest frequency
midrange
(max value + min value) / 2
range
max value - min value
standard deviation
determines how much the data values deviate from the mean of the data set (x-x̅ )
variance
standard deviation^2
s
standard deviance found using sample data
σ
standard deviance found using population data
range rule of thumb
based on the idea that roughly 95% of the data lies within 2 standard deviations of the mean
minimum usual value
[(mean)-2]x[standard deviance]
maximum usual value
[(mean)+2]x[standard deviance]
z-score
number of standard deviations a data value is from the mean of the data set
z-score formula (sample notation)
(x-x̅)/s
z-score formula (population notation)
(x-μ)/σ
rounding rule for z-score
round to 2 decimal places
quartiles
divides the data set into 4 groups
5-number summary
min data value, Q1, median, Q3, max data value
skeletal boxplot
graph used to compare the 5 number summary of 2 different data sets together
modified boxplot
graph used to determine outliers
