Statistics

Question 1

What is statistics ?

Answer 1

It is the collection, tabulation,analysis,interpretation and presentation of data
Nb each process is important to note

Question 2

Measures of central tendency is

Answer 2

The representative values of a given set of data arithmetic mean, median

Question 3

Formulas for mean, standard deviation and meaning of statistic and parameter

Answer 3

Mean for sample(x bar)= N
EXi/N
Mean for population = N
EXi/N
Standard deviation for sample = square root of Ef(x-x bar)^2/Ef
Standard deviation for population = square root of Ef(x-|u)^2/Ef
A statistic is a characteristic of a sample
A parameter is a population estimate

Question 4

Formula for median
What is kurtosis ?
What is skewness?
What are some measures of skewness

Answer 4

(n+1)/2 (position of median)

Kurtosis is used to measure the Peakness of data
Skewness is a measure of symmetry and asymmetry
Measures of skewness :
Pearson’s first coefficient of skewness =(mean-mode)/standard deviation
Quartile coefficient of skewness=(Q3-2Q2+Q1)/Q3-Q1
Percentile =(P90-2P50+P10)/P90-P10
Nb: a set of observations in arithmetic progression the mean is equal to median

Question 5

Coefficient of kurtosis

Answer 5

Is =m4/m2=S^4/(S^2)^2
Nb:we have mesokurtic(Nk, normal)
Platykurtic(negative)
Leptokurtic(positive ) and always subtract 3 to determine if it is mesokurtic platykurtic or leptokurtic