Key Concepts

Key Concepts

• Calculate the mean of a set of numbers.
  1. Write the formula for the mean \(\text{mean}=\frac{\text{sum of values in data set}}{n}\)
  2. Find the sum of all the values in the set. Write the sum in the numerator.
  3. Count the number, n, of values in the set. Write this number in the denominator.
  4. Simplify the fraction.
  5. Check to see that the mean is reasonable. It should be greater than the least number and less than the greatest number in the set.
• Find the median of a set of numbers.
  1. List the numbers from least to greatest.
  2. Count how many numbers are in the set. Call this \(n\).
  3. Is \(n\) odd or even?
     If \(n\) is an odd number, the median is the middle value.
     If \(n\) is an even number, the median is the mean of the two middle values
• Identify the mode of a set of numbers.
  1. List the data values in numerical order.
  2. Count the number of times each value appears.
  3. The mode is the value with the highest frequency.