Descriptive Statistics

Question 1

What are the central values from statistics?

Answer 1

Mean
Median
Mode
Quantiles

Question 2

What are the dispersing values?

Answer 2

Range
Standard deviation
Interquartile range
Minimum and maximum

Question 3

Formula for mean?

Answer 3

Sum of data/ number of data

Question 4

What is Range, Median and Mode

Answer 4

Range= Max-Min
Median= middle number on arrangement by ascending order
Mode= most occurring

Question 5

What are the quartile?

Answer 5

Q1: middle number between Min & Median
Q3: middle number between Median and Max.

•for even numbers find average of middle numbers

Question 6

What is interquartile range?

Answer 6

Q3 - Q1

Question 7

What is in the 3- no. association?

Answer 7

Mean, SD and n

N = total number of values

Question 8

5-no. association?

Answer 8

Quartile and Interquartile range

Question 9

What is Standard deviation and Variance?

Answer 9

V = (x1 - mean)^2 / n-1
SD = square root of answer

Question 10

Standard Error Mean?

Answer 10

SEM = SD/ square root of n

Question 11

What is skewness?

Answer 11

Measure of degree of symmetry

•to right - S<0
in middle - S=0
to left - S>0

Question 12

What is kurtosis?

Answer 12

Measure of degree of peakness

Small peak- K<0 (platykurtic)
Mid. peak- K=0 (mesokurtic)
High peak- K>0 (leptokurtic)

Question 13

3 sigma rule?

Answer 13

u - sigma, u + sigma =68% (34|34)
u - 2sigma, u + 2sigma=95% (13.5|13.5)
u - 3sigma, u + 3sigma=99.7% (2.35|2.35)

Question 14

Solving with 3 sigma rule?

Answer 14

Finding range of values= (%/100) x mean
Between two sigma =(% - %)/2

Z= expected mean - mean/ SD
P(z)= 1- z(table value)

Question 15

When to identify an outlier?

Answer 15

Falls between Q1-(1.5xIQR) & Q3-(1.5xIQR)