Question

According to the empirical rule for a normal distribution...

		99% of cases fall within 1 standard deviation of the mean
		88 cases fall within 2 standard deviations of the mean
		approximately 95% of cases fall withing 2 standard deviations of the mean
		100% of cases fall withing 3 standard deviations of the mean

Answer 1

Solution
For a bell-shaped distribution ( Normal distribution )

1) 68% of the data falls within 1 standard deviation from mean
that is :
2) 95% of the data falls within 2 standard deviations from mean
that is :

3) 99.7% of the data falls within 3 standard deviations from mean
that is :

Thus According to the empirical rule for a normal distribution:

approximately 95% of cases fall within 2 standard deviations of the mean

Thus correct option is third option.