# Understanding standard deviation and z score.

Please answer the following question:

- Explain thoroughly, the concept of standard deviation.

- How does range affect standard deviation?

- What is a z-score, and how do z-scores relate to the mean of a set of data?

- Generally speaking, how is the percentage of data which lies in between two z-scores calculated?

https://brainmass.com/statistics/z-test/understanding-standard-deviation-and-z-score-4728

#### Solution Preview

The range is the simplest measure of spread or dispersion: It is equal to the difference between the largest and the smallest values. The range can be a useful measure of spread because it is so easily understood. However, it is very sensitive to extreme scores since it is based on only two values.

The variance is a measure of how spread out a distribution is. It is computed as the average squared deviation of each number from its mean. The ...

#### Solution Summary

Standard deviation and z score are discussed.