Histogram and density plots in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a histogram used for in data visualization?

A histogram shows how data values are spread across different ranges or bins. It helps us see the shape and frequency of data.

beginner

How does a density plot differ from a histogram?

A density plot shows a smooth curve estimating the data distribution, while a histogram uses bars to show counts in bins.

beginner

In R, which function creates a histogram?

The function hist() creates a histogram in R.

intermediate

What does the density() function in R do?

It calculates the kernel density estimate, which is used to draw a smooth density plot.

intermediate

Why might you overlay a density plot on a histogram?

Overlaying helps compare the smooth estimated distribution with the actual data counts, giving a clearer picture of data shape.

Which R function is used to create a histogram?

A barplot()

B plot()

C hist()

D density()

The hist() function creates histograms in R.

What does a density plot represent?

A Exact counts of data points

B A smooth estimate of data distribution

C Data sorted in ascending order

D A bar chart of categories

Density plots show a smooth curve estimating how data is distributed.

Which argument in hist() controls the number of bins?

A xlab

B col

C main

D breaks

The breaks argument sets the number or positions of bins.

What R function helps calculate values for a density plot?

A density()

B hist()

C summary()

D mean()

The density() function computes kernel density estimates.

Why overlay a density plot on a histogram?

A To compare smooth distribution with actual data counts

B To hide the histogram bars

C To change the color of bars

D To sort data points

Overlaying helps visualize both the smooth estimate and the raw data distribution.

Explain how to create a histogram and a density plot in R and why you might use both together.

Think about bars vs smooth curves and how they show data differently.

Describe the role of the 'breaks' argument in the hist() function.

Consider how changing bins changes the histogram look.