Question

Which of the following, on its own, is the least useful method for assessing if the data follow a normal distribution?

Check if the distribution is unimodal and symmetric.
Check if the points are on a straight line on a normal probability plot.
Check if the mean and median are equal.
Check if 68% of the data are within 1 SD of the mean, 95% of data are within 2 SDs of the mean, and 99.7% of data are within 3 SDs of the mean.

Answer 1

Among the options provided, "Check if the distribution is unimodal and symmetric" is the least useful method for assessing if the data follow a normal distribution.

While unimodality (having a single peak) and symmetry can be characteristics of normal distributions, they do not guarantee normality. Other distributions can also be unimodal and symmetric, but not normally distributed.

The other methods mentioned, such as checking if the points form a straight line on a normal probability plot, comparing the mean and median, and assessing the percentages within specific standard deviations of the mean, are more direct and reliable ways to assess whether the data follow a normal distribution.

Step-by-step explanation: