Learn Calculating Aggregated Metrics | Grouping and Aggregation in R

Understanding aggregated metrics is essential for anyone working with data. When you analyze datasets, you often need to summarize information by calculating averages, counts, or other statistics that help you make informed decisions. These aggregated metrics allow you to see patterns, compare groups, and draw conclusions that would be hidden in raw, row-level data.


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library(dplyr)

# Sample sales data
sales_data <- data.frame(
  category = c("A", "A", "B", "B", "B", "C"),
  sales = c(100, 150, 200, 220, 180, 300)
)

# Calculate mean and median sales per product category
summary <- sales_data %>%
  group_by(category) %>%
  summarise(
    mean_sales = mean(sales),
    median_sales = median(sales)
  )

library(knitr)
kable(summary)

In this example, you group the sales data by category and then use the summarise() function to calculate both the mean and median sales for each product category. The mean gives you the average sales value, while the median shows the middle value when sales are ordered. Both metrics help you understand typical sales amounts, but the median is less affected by unusually high or low sales, making it useful when your data has outliers.


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# Count the number of sales per category
count_summary <- sales_data %>%
  group_by(category) %>%
  summarise(
    sales_count = n()
  )

kable(count_summary)

The n() function, used inside summarise(), counts the number of rows in each group. In the previous code, sales_count tells you how many sales entries exist for each product category. This is especially helpful for understanding how much data you have in each group, which can affect the reliability of your aggregated metrics.

Definition

An aggregated metric is a summary statistic calculated from grouped data. Common aggregated metrics in analytics include mean, median, sum, count, minimum, and maximum. These metrics help you summarize and compare different groups within your data.

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Section 3. Chapter 2

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              123456789101112131415161718
            
library(dplyr)

# Sample sales data
sales_data <- data.frame(
  category = c("A", "A", "B", "B", "B", "C"),
  sales = c(100, 150, 200, 220, 180, 300)
)

# Calculate mean and median sales per product category
summary <- sales_data %>%
  group_by(category) %>%
  summarise(
    mean_sales = mean(sales),
    median_sales = median(sales)
  )

library(knitr)
kable(summary)


              12345678
            
# Count the number of sales per category
count_summary <- sales_data %>%
  group_by(category) %>%
  summarise(
    sales_count = n()
  )

kable(count_summary)

Definition

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 2

Calculating Aggregated Metrics

1. What is an aggregated metric?

2. How do you calculate the number of items in each group using dplyr?

3. Why might you want to calculate both mean and median for a group?

Calculating Aggregated Metrics

1. What is an aggregated metric?

2. How do you calculate the number of items in each group using dplyr?

3. Why might you want to calculate both mean and median for a group?