Stats - Quick Review

5. Show a picture and explain what 1 and 2 standard deviations from the mean are and what this means for normally distributed data in terms of how many of the values lie in this range.

Standard deviations can be used to decide whether the differences between two related means are significant or not. If standard deviations are much larger than the difference between the means, then the differences in the means are highly unlikely to be significant. On the other hand, when standard deviations are much smaller than the differences between the means, then the differences between the means is almost certainly significant.