Histograms

Question 1

What is often refered to as bins

Answer 1

The range of the data divided into intervals of equal width

Question 2

What is a histogram

Answer 2

The plot of bars, one for each bin with heights proportional to the number of observations in the corresponding bin

Question 3

What does the height of the bar represent

Answer 3

Number in each interval

Question 4

Can the number expressed as a proportion of the total number of observations in the sample give a picture of the data distribution which is not DEPENDANT OF SAMPLE SIZE

Answer 4

Yes

Question 5

Why must analysts exercise judgement in the choice of number of bins (intervals)

Answer 5

Small number of bins- very little indication how the heights are distributed
Increasing the number of the bins can give you a better picture
If there are too many bins there will be too little smoothing of the data and the histogram will start to look jagged

Question 6

What does a histogram show

Answer 6

The entire sample and allows the FULL DISTRIBUTION of the SAMPLE to be viewed not just a graphical version of the five number summery

Question 7

When a sample size increases…

Answer 7

Deeper aspects of the nature of the distribution may become more apparent

Question 8

Are all histograms normally distributed

Answer 8

The data is not always normally distributed i.e. bell shaped distribution