Measures of Variability

Front

What are the four measures of variability?

Back

Range, Average Deviation, Standard Deviation, Variance.

Front

What is the formula for calculating the range?

Back

r = H - L, where r is the range, H is the highest value, and L is the lowest value.

Front

How do you determine the range of ungrouped data?

Back

1. Arrange the data in ascending order. 2. Find the difference between the largest and smallest values.

Front

What is Average Deviation?

Back

Average Deviation is the sum of absolute deviations of the arithmetic mean divided by the number of cases.

Front

What is the formula for Average Deviation (AD)?

Back

AD = (Σ|x - mean|) / N, where x is the individual score, mean is the average, and N is the number of scores.

Front

What is Standard Deviation?

Back

Standard Deviation is a measure of the amount of variation of the values of a variable about its mean.

Front

What does a smaller Standard Deviation indicate?

Back

A smaller Standard Deviation indicates a smaller spread of the range around the mean.

Front

What is Variance?

Back

Variance is the square of the standard deviation and measures how far each number in the set is from the mean.

Front

What are the steps to calculate Variance?

Back

1. Calculate the mean of the data. 2. Find each data point's difference from the mean. 3. Square each of these values. 4. Add up all squared values. 5. Divide by n - 1 (for a sample) or N (for the total population).

Front

What is the relationship between Standard Deviation and Variance?

Back

Variance is the square of the Standard Deviation.