elementary statistics ulm test 1

statistics

N

number of values in a set of population data

n

number of values in a sample data set

Mu

average of population data

x bar

the average of sample data

x

data value

o²

population variance

∑

summation

σ

population standard deviation

s²

sample variance

s

sample standard deviation

r

correlation coefficient

mean

average

median

number in the middle of the data set

mode

most occurring number(s) in a data set

quartile

four sections of data

precentile

100 sections

IQR

Q3-Q1=IQR

Lower Fence

Q1-1.5(IQR)

Upper Fence

Q3+1.5(IQR)

5 number summary

minimum Q1 Q2 Q3 maximum

boxplot

visual of the 5 number summary

standard score/ z score

z=(x-mu)/σ

mean of group data

middle of each class

correlation definition

determines weather a relationship between variables exist

correlation calulation

-1<r<1

pearson correlation coefficient table

tells you if you can have a line of best fit

variance

is the average of the squares of the distance each value is from the mean

types of distribution

left skewed, right skewed, bell shaped, uniform

Discrete

counts something

continuous

cant be counted

Branches of statistics

Descriptive and Inferential

census

100% of people

random sample

random generation, equal chance

startified

same number person from each group

cluster

100% of people in one group

systematic

every 5th person in line

convenience sample

convenient to the person sampling

marginal utility formula

x-mu

Variance formula

(x-mu)²

1 standard deviation from the mean

68%

2 standard deviations from the mean

95%

3 standard deviations from the mean

97.7%