Math 122 Formulas

Front 1

Frequency of the class divided by the number of observations

Back 1

Relative frequency formula in words
pg 34

Front 2

Equal to the range of the data values divided by the number of classes

Back 2

Approximate class width in words
pg 40

Front 3

Approximate class width in words

Back 3

Equal to the range of the data values divided by the number of classes pg 40

Front 4

Relative frequency formula in words
pg 34

Back 4

Frequency of the class divided by the number of observations
pg 34 / 64

Front 5

Sample mean in words

Back 5

The sum of all the values of the observations divieded by the number of observations

Front 6

First and third Quartile

Back 6

25th and 75th Percentile

Front 7

Percentile in words

Back 7

Arange data in ascending order
compute I = the desired percentile position divided by 100
Multiply the quoteint by the number of observations
if I is an integer then the percentile value for that place is the average of i plus i+1
if it is not an integer round i up to get the position of the percentile in question

Front 8

Sample variance in words

Back 8

The sum of the square of the difference of each observation and the mean
This diference is then divided by the number of observations minus 1 for a sample

Front 9

Standard deviation

Back 9

The square root of the variance

Front 10

Coeficiant of variation in words

Back 10

standard deviation divided by the mean
this quotient multiplied by 100 is the percentage
indicates the size of the std dev in relation to the mean

Front 11

Z score in words

Back 11

Calculate the quoteint of the diference of measurment and the mean and standard deviation

Front 12

Chebyshev in words

Back 12

AT LEAST 1 minus 1 divided by the z number squared will be within z standard deviations of the mean

Front 13

Empirical rule in words

Back 13

for data with a bell shape aproximatly 68 % of data values within one standard deviation and 95 % within two standard deviations