Stats and prob-4th quarter examination

Mean

-Most common used measure central tendency

-Average and generally affected by outliers

X̄

Mean

ΣX

Sum of all scores

n

Number of scores

Median

-Midpoint of the data. It will be either a specific value or will between two values

-Should be arrange from least to greater

Mode

-Referred to as the most frequently occuring value in a given set of data

Group data

-Median

-Mean

-Mode

Mean formula

Fx

The product of frequency and class mark

N

Total of frequencies

Lower boundary (LB)

Lower score-0.5

Classmark

lower score plus upper score divide by two

CF (Cumulative frequency)

Frequency (addition)

Median formula

Total frequency

lbmc

lower boundary of median class

fmc

Frequency of median class

Cw

Class width

Cf

Cumulative frequency before preceding the median class

Mode formula

lbmc

lower boundary of modal class

D1

Difference of the modal class and the class preceding it

D2

Difference of the modal class and the class preceding it

Measure of dispresion

A measure of variability of a set of dataisa number that conveys the idea spread for the data set

Measure of dispresion types:

•Range

•Standard deviation

•Varaince

Range

Measures the distance between the largest and the smallest values and gives an idea of the spread of the data set

Formula of range

(R)=Highest value- Lowest value

Standard deviation

The standard deviation is a measure of how spread out numbers are

The greek letter sigma

Standard deviation the population

Standard deviation of the sample

Variance

The variance for a given data set is the square of the standard deviation of the data

Variance of the population

Variance of the sample