A short introduction to R - Exercises

Q & A’s

Please place your answers in the R Markdown code blocks or write the answers next to the A:

• Q: Simple calculus: what is the R code to calculate 5.3278 * 8.3?
• A:

5.3278 * 8.3

## [1] 44.22074

• Q: Simple calculus: what is the R code to calculate the square route of 64?
• A:

sqrt(64)

## [1] 8

• Q: Simple calculus: what is the R code to calculate 2 to the power of 16?
• A:

2^16

## [1] 65536

• Q: What is the R code to calculate how many kHz 44100 Hz is?
• A:

44100 / 1000

## [1] 44.1

• Q: In R the object pi defaults to the mathematical constant of the same name. What is the R code to calculate the area of a circle that has a radius of 10cm (reminder: A = pi*r^2)
• A:

pi * 10^2

## [1] 314.1593

• Q: What is the R code to create a sequence from 0 to 2*pi that has a length of 16000?
• A:

vals = seq(0, 2*pi, length.out = 16000)

• Q: What is the R code to (a.)) calcualte and (b.)) visualize the sinus values for the above sequence?
• A:

# a.)
vals_sin = sin(vals)
# b.)
plot(vals_sin)

• Q: Given a sample rate of 16000: how many Hz is the sine wave in the above plot?
• A: 1 Hz

Task(s)

• Create a R Markdown file (output: html_document) containing the heading: “I am great at math”, the text “Look at me go:” and the R code block 2 + 2

• Create a R script containing the same information without the Markdown syntax

• Q: Given the above two files: what are the adv. of R Markdown?

• A: Explicit separation between R code and written word which would have to be placed in comments otherwise.