How does adding more data to a data set impact statistical measures?

• A. It does not affect any measures.
• B. It changes the mean, median, mode, and range.
• C. It only changes the mean.
• D. It only changes the range.

Answer: (B)

Adding more numbers to a data set can alter several summary numbers you use to describe it. The mean, or average, changes because you’re changing the total sum and how many values there are, so the overall average can go up or down. The median, the middle value when the data are ordered, can shift as new numbers are added and the middle position moves. The mode, the most frequent value, can switch if the new data introduces a new most common value or increases the frequency of an existing one. The range, the difference between the largest and smallest values, can grow if the new data extends beyond the current extremes, or stay the same if it stays within the existing span. So adding data has the potential to change all of these measures.