R Percentile

A percentile is a statistical measure that indicates the value below which a percentage of data falls.

For example, the 70th percentile is the value below which 70% of the observations may be found.

Calculate Percentile in R

In R, we use the quantile() function to calculate the percentile. For example,

marks <- c(97, 78, 57, 64, 87)

# calculate 70th percentile of marks
result <- quantile(marks, 0.70)

print(result)

Output

70% 
85.2

In the above example, we have used the quantile() function to calculate the 70th percentile of the marks vector. Notice the code,

quantile(marks, 0.70)

Here,

• marks - a vector whose percentile is to be calculated
• 0.70 - a percentile value. For the 70th percentile we use 0.70 argument

Calculate Multiple Percentile a Vector in R

We use the c() function to pass multiple percentiles to quantile() at once in R. For example,

marks <- c(97, 78, 57, 64, 87)

# calculate 70th, 50th, 80th percentile of marks
result <- quantile(marks, c(0.7, 0.5, 0.8))

print(result)

Output

70%  50%  80% 
85.2  78.0   89.0

Here, we have used the c() function to pass multiple percentiles: 0.7, 0.5, 0.8 to quantile() all at once.

Hence, quantile() returns 70th, 50th and 80th percentile of marks respectively.

Calculate Percentile in R Data Frame

R allows us to calculate the percentile of specific data frame columns. For example,

# Create a data frame
dataframe1 <- data.frame (
  Name = c("Juan", "Kay", "Jay", "Ray", "Aley"),
  Age = c(22, 15, 19, 30, 23),
  ID = c(101, 102, 103, 104, 105)
)

# calculate 55th and 27th percentile of the Age column
result <- quantile(dataframe1$Age, c(0.55, 0.27))

print(result)

Output

 55%   27% 
22.20 19.24

Here, we have calculated the 55th and 27th percentile of the Age column of the dataframe1 data frame.