Question

Without using a normal curve table, about what percentage of scores on a normal curve are (a) above the mean (b) between the mean and 1 SD above the mean (c) between 1 and 2 SDs above the mean, (d) below the mean, (e) between the mean and 1 SD below the mean, and (f) between 1 and 2 SDs below the mean?

a) (a) 50%, (b) 34%, (c) 13.5%, (d) 50%, (e) 34%, (f) 13.5%
b) (a) 68%, (b) 34%, (c) 13.5%, (d) 32%, (e) 50%, (f) 16%
c) (a) 84%, (b) 34%, (c) 13.5%, (d) 16%, (e) 50%, (f) 34%
d) (a) 50%, (b) 16%, (c) 34%, (d) 50%, (e) 13.5%, (f) 32%

Answer 1

According to the Empirical Rule, the percentage of scores on a normal curve can be estimated.

Step-by-step explanation:

For a normal distribution, the Empirical Rule states that:

• Approximately 68% of the data is within one standard deviation of the mean.
• Approximately 95% of the data is within two standard deviations of the mean.
• More than 99% of the data is within three standard deviations of the mean.

Therefore, using this rule, the percentage of scores on a normal curve are:

• (a) Above the mean: About 50%
• (b) Between the mean and 1 SD above the mean: About 34%
• (c) Between 1 and 2 SDs above the mean: About 13.5%
• (d) Below the mean: About 50%
• (e) Between the mean and 1 SD below the mean: About 34%
• (f) Between 1 and 2 SDs below the mean: About 13.5%