Data representation

Question 1

wWhat is an outlier?

Answer 1

An extreme value that falls outside the data set

Question 2

How many tests are there for outliers and what are their names?

Answer 2

1. Quartile test
2. Mean and standard deviation test

Question 3

Quartile test

Answer 3

Upper limit = Q3 + k(qQ3-Q1)
Lower limit = Q1 -k(Q3-Q1)

If data value > upper limit then it is an outlier
Data value < lower limit then it is also an outlier

Question 4

Mean and standard deviation test

Answer 4

upper limit= mean(x) + K(σx)
lower limit = mean(x) - k(σx)

• σ is standard deviance

data value > upper limit then its an outlier
data value < lower limit then it is an outlier

Question 5

When working out Quartile values and the value is a decimal number, what should you do?

Answer 5

Round up and take that value
e.g. value is 3.4 therefore take the 4th value

Question 6

When working out Quartile values and the value is a whole number, What should you do?

Answer 6

Take an average
e.g. 6 … take an average of the 6th and 7th value

Question 7

In a Histogram, what does area of the bar represent?

Answer 7

It is proportional to the frequency

A = kf

A- area of bar
K - constant
F- frequency

Question 8

What happens when K= 1 in a histogram?

Answer 8

Frequency Density = frequency/ class width