Question

In a normal curve, roughly what percent of all cases fall within plus or minus two standard deviations

Answer 1

We know that the total area under the normal curve is 100%. According to the empirical rule of Normal distribution:

Approximately, 68% of data lies within
`\pm1` standard deviations of mean.

Approximately, 95% of data lies within
`\pm2` standard deviations of mean.

Approximately, 99.7% of data lies with
`\pm3` standard deviations of mean,

Therefore, in a normal curve, roughly 95% of all cases fall within plus or minus two standard deviations.