Given the normal distribution with mean 100 and standard deviation 10, find the number of standard deviations the measurement is from the mean. Express the answer as a positive number in decimal form.

Measurement = 139

Question

Given the normal distribution with mean 100 and standard deviation 10, find the number of standard deviations the measurement is from the mean. Express the answer as a positive number in decimal form.

Measurement = 139

anonymous · Answer

$$
z = \frac{x-\mu}{\sigma} = \frac{139-100}{10} =\ldots
$$

anonymous · Answer

129?

anonymous · Answer

The distance from the mean is just: $|139-100| = |39|=39$.  You need to divide it by the standard deviation $10$, to get it into terms of the number of standard deviations away it is.