Calculate mean, median, mode, range, and standard deviation
Mean: Sum all values and divide by the count. Median: Sort the data and find the middle value (or average of the two middle values for even counts). Mode: Identify the most frequently occurring value. Standard Deviation: Calculate the square root of the average squared differences from the mean.
Descriptive statistics summarize large datasets into understandable numbers. They're essential in science, business, healthcare, education, and everyday decision-making. Understanding whether your data is normally distributed, skewed, or contains outliers helps you draw accurate conclusions and make informed choices based on evidence rather than intuition.
Use mean for symmetric data without outliers (test scores, temperatures). Use median when data is skewed or has outliers (income, house prices). Use mode for categorical data or finding the most common value (shoe sizes, survey responses). Standard deviation tells you how spread out values are from the average.
Always examine your data visually before calculating statistics—a histogram reveals patterns that numbers alone may miss. Check for outliers that could skew your mean. Report multiple measures together for a complete picture. When comparing datasets, standard deviation matters as much as the mean—two groups can have identical averages but very different distributions.
Mean is the average (sum divided by count). Median is the middle value when sorted. Mode is the most frequent value. Each measures 'center' differently and is useful in different situations.
Standard deviation measures how spread out numbers are from the mean. A low standard deviation means values are close to the mean; high means they're spread out.
Use median when your data has outliers (extreme values) that would skew the mean. For example, median income is often more representative than mean income because a few very high earners can inflate the mean.