Dec 3 B2 Stats Ch 2.4 Measures of Variation

Front

What is the first step in calculating variance?

Back

Find the mean.

Front

How do you calculate the standard deviation?

Back

Take the square root of the variance.

Front

What is the formula for variance?

Back

Variance = (Σ(x - mean)²) / N, where x is each data point, mean is the average, and N is the number of data points.

Front

What percent of data falls within 1 standard deviation of the mean in a normal distribution?

Back

68%.

Front

What percent of data falls within 2 standard deviations of the mean in a normal distribution?

Back

95%.

Front

What does variance measure in a data set?

Back

How spread out each data value is from the mean.

Front

What is the relationship between variance and standard deviation?

Back

Standard deviation is the square root of variance.

Front

If the variance of a data set is 0, what does that indicate?

Back

All data points are identical; there is no variation.

Front

What is the range of a data set?

Back

The difference between the maximum and minimum values.

Front

How does increasing the spread of data affect variance?

Back

Variance increases as the spread of data increases.