Graphics tools :

Graphics tools - various type of plots

Appropriate number and choice of plots in analysis provides better inferences.Graphics tools - various type of plots

- 2D & 3D plots,
- scatter diagram
- Pie diagram
- Histogram
- Bar plot
- Stem and leaf plot
- Box plot ....

In R, such graphics can be easily created and saved in various formats.

- Bar plot
- Pie chart
- Box plot
- Grouped box plot
- Scatter plot
- Coplots
- Histogram
- Normal QQ plot ...

**Bar plots :-**

→ Visualize the relative or absolute frequencies of observed values of a variable.

→ It consists of one bar for each category.

→ The height of each bar is determined by either the absolute frequency or the relative frequency of the respective category and is shown on the

*y-axis*.

barplot (x, width = 1, space = NULL ,...)

> barplot (table (x) )

> barplot (table (x) / length (x) )

Example :-

Code the 10 persons by using, say 1 for male (M) and 2 for female (F).

M, F, M, F, M, M, M, F, M, M

1, 2, 1, 2, 1, 1, 1, 2, 1, 1

> gender <- c(1, 2, 1, 2, 1, 1, 1, 2, 1, 1)

> gender

[1] 1 2 1 2 1 1 1 2 1 1

Example :-

> barplot (gender)

Do you want this ?

2 categories

M = 7

F = 3

**Pie diagram :-**

Pie charts visualize the absolute and relative frequencies.

A pie chart is a circle partitioned into segments where each of the segments represents a category.

The size of each segment depends upon the relative frequency and is determined by the angle (frequency x 360 degree).

pie (x, labels = names (x), ...)

Example :-

> pie (gender)

**Histogram :-**

Histogram is based on the idea to categorize the data into different groups and plot the bars for each category with height.

The area of the bar (= height x width ) is proportional to the relative frequency.

So the width of the bars need not necessarily to be the same

hist (x) # show absolute frequencies

hist (x, freq=F) # show relative frequencies

see help ("hist") for more details

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