Measures of Central Tendency of Data Flashcards
What is mean (arithmetic mean)?
the average of all data points
What is the formula for mean?
(x1 + x2 + x3 + … + xn)/n, or ∑x/n, or add all the data points together and divide by the number of values there are.
What is ∑?
a greek letter called “sigma”, which means “sum of…”
What is the formula for weighted average?
a * m + b * n + c * p–/m + n + p–, where a, b, and c are mean values of sets A, B, and C, and m, n, and p are number of data points in the respective set.
What are the requirements for calculating weighted average?
If there are two or more sets with different amount of data points
What is median?
the middle data point after arranging all data points in ascending or descending order
How do you find the median of an even number of data points?
You take the average of the middle two data points
Is median sensitive to outlier data points?
No
What is the best representative of the central location of data?
the median
What is mode?
The most occurring data points; the data point with the most frequency of repetition
What is range?
the difference between the maximum and minimum data points
What is the lower quartile?
25% of the data points are below this data point
What is the upper quartile?
25% of the data points are above this data point
What is standard deviation?
a measure of the spread of the data points around the mean value
