Consider the standard normal curve given. A graph shows the horizontal axis numbered 20 to 40. 30 is highlighted in an orange outline. Variance = 5 and is highlighted in an orange outline. The line shows an upward trend to from 20 to 30 then a downward trend from 30 to 40.
The mean is
.

The standard deviation is
.

The data point 37 is
one standard deviation from the mean.

There are two major tests of readiness for college: the act and the sat. act scores are reported on a scale from 1 to 36. the distribution of act scores in recent years has been roughly normal with mean µ = 20.9 and standard deviation s = 4.8. sat scores are reported on a scale from 400 to 1600. sat scores have been roughly normal with mean µ = 1026 and standard deviation s = 209. reports on a student's act or sat usually give the percentile as well as the actual score. the percentile is just the cumulative proportion stated as a percent: the percent of all scores that were lower than this one. tanya scores 1260 on the sat. what is her percentile (± 1)?