The quantile() function in R used to calculate sample quantiles values from dataset.The quantile are values that divide dataset into equal groups.

The following method shows how you can do it with syntax.

Method: Use quantile() Function

quantile(x, probs = seq(0, 1, 0.25),na.rm=FALSE)


x : name of dataset probs : numeric dataset of probabilities na.rm : used for whether to remove NA values.

The following examples show how to use quantile() function in R.

## Apply quantile() Function to Calculate Quantile Values of Dataset

Let’s create numeric dataset to calculate its quantile values:

# Create dataset
data <- c(78,89,85,84,81,79,77,85,85,81,78,89,84,84,81,80)

# Find quantile values
q1 <- quantile(data,probs=seq(0,1,1/4))

# Show quartile values
print(q1)

# Find quintiles values
q2 <- quantile(data,probs=seq(0,1,1/5))

# Show quintiles values
print(q2)

# Find deciles values
q3 <- quantile(data,probs=seq(0,1,1/10))

# Show deciles values
print(q3)


Output:

 0%   25%   50%   75%  100%
77.00 79.75 82.50 85.00 89.00

0%  20%  40%  60%  80% 100%
77   79   81   84   85   89

0%  10%  20%  30%  40%  50%  60%  70%  80%  90% 100%
77.0 78.0 79.0 80.5 81.0 82.5 84.0 84.5 85.0 87.0 89.0


Here in the above code we created numeric dataset then we find the quantile values from dataset using quantile() function.

## Apply quantile() Function to Calculate Quantile Values of Column of Data Frame

Let’s see how we can apply quantile() function column of data frame:

# Create data frame
df <- data.frame(Pressure=c(12.39,11.25,12.15,13.48,13.78,12.89,12.21,12.58),
Temperature=c(78,89,85,84,81,79,77,85),
Humidity=c(5,7,1,2,7,8,9,4))

# Calculate quartiles for 'Pressure'
q <- quantile(df\$Pressure,probs = seq(0, 1, 1/4))

# Show quartile value
print(q)


Output:

  0%     25%     50%     75%    100%
11.2500 12.1950 12.4850 13.0375 13.7800


Here in the above code we calculate quartile value for Pressure column of data frame using quantile() function.

## Apply quantile() Function to Calculate Quantile Values of Entire Data Frame

You can calculate the quartile value for entire data frame using quantile() function.

# Create data frame
df <- data.frame(Pressure=c(12.39,11.25,12.15,13.48,13.78,12.89,12.21,12.58),
Temperature=c(78,89,85,84,81,79,77,85),
Humidity=c(5,7,1,2,7,8,9,4))

# Calculate quartiles for data frame
q <- sapply(df,function(x) quantile(x,probs=seq(0,1,1/4)))

# Print quartile values
print(q)


Output:

 Pressure Temperature Humidity
0%    11.2500       77.00     1.00
25%   12.1950       78.75     3.50
50%   12.4850       82.50     6.00
75%   13.0375       85.00     7.25
100%  13.7800       89.00     9.00


The output shows quartile values for each variable of data frame.

By taking reference of above examples you can calculate quartile values for any dataset.