Statistics How-To Guides

Step-by-step instructions for the most common Statistics questions.

How to Calculate the Mean of a Dataset

  1. Add values: Sum all numbers in the dataset.
  2. Count values: Count how many numbers there are.
  3. Divide: Divide the sum by the count to get the mean.

How to Calculate the Median

  1. Sort values: Sort the dataset from smallest to largest.
  2. Find middle: Locate the middle value.
  3. Average: If even count, average the two middle values.

How to Calculate the Mode

  1. Count occurrences: Count how many times each value occurs.
  2. Identify mode: The number(s) with highest frequency is the mode.
  3. Multiple modes: If more than one number has the same frequency, list all as modes.

How to Calculate the Range

  1. Find min: Identify the smallest value in the dataset.
  2. Find max: Identify the largest value in the dataset.
  3. Subtract: Subtract the minimum from the maximum to get the range.

How to Calculate Variance

  1. Find mean: Calculate the mean of the dataset.
  2. Subtract mean: Subtract the mean from each data point and square the result.
  3. Average squares: Take the average of these squared differences for the variance.

How to Calculate Standard Deviation

  1. Find variance: Calculate the variance of the dataset.
  2. Take square root: Take the square root of the variance to find standard deviation.
  3. Interpret: The standard deviation indicates data spread around the mean.

How to Construct a Frequency Table

  1. List values: List each unique value in the dataset.
  2. Count occurrences: Count how many times each value occurs.
  3. Fill table: Create a table with value and frequency columns.

How to Create a Histogram

  1. Choose bins: Decide on intervals (bins) for data.
  2. Count frequencies: Count how many data points fall into each bin.
  3. Draw bars: Draw bars proportional to frequencies for each bin.

How to Calculate Probability

  1. Define event: Define the event whose probability you want.
  2. Count favorable outcomes: Count the number of outcomes that satisfy the event.
  3. Divide by total outcomes: Divide favorable outcomes by total possible outcomes.

How to Calculate Conditional Probability

  1. Define events: Identify event A and event B.
  2. Find intersection: Determine probability of A and B occurring together.
  3. Divide: Divide intersection probability by probability of B to get conditional probability.