Which statistic is calculated by adding all values and dividing by the number of observations?

Which statistic is calculated by adding all values and dividing by the number of observations?

• A. Mean
• B. Median
• C. Mode
• D. Range

Answer: (A)

Calculating the average by adding all values and dividing by how many observations gives the mean. This measures the center of a data set by treating every value equally and summarizing the data with a single representative number. For example, with values 2, 4, and 6, the mean is (2 + 4 + 6) / 3 = 4. The mean has convenient properties used in many analyses, such as the sum of deviations from the mean being zero and the ability to shift all data by the same amount without changing the relationship among observations. However, it can be sensitive to extreme values, so in highly skewed data the median might better reflect a typical value. Other statistics describe different aspects: the median is the middle value when the data are ordered, the mode is the most frequent value, and the range is the difference between the largest and smallest values.

Calculating the average by adding all values and dividing by how many observations gives the mean. This measures the center of a data set by treating every value equally and summarizing the data with a single representative number. For example, with values 2, 4, and 6, the mean is (2 + 4 + 6) / 3 = 4. The mean has convenient properties used in many analyses, such as the sum of deviations from the mean being zero and the ability to shift all data by the same amount without changing the relationship among observations. However, it can be sensitive to extreme values, so in highly skewed data the median might better reflect a typical value.

Other statistics describe different aspects: the median is the middle value when the data are ordered, the mode is the most frequent value, and the range is the difference between the largest and smallest values.