Question

A standardized test is designed so that scores have a mean of 50 and a standard deviation of 4.

What percent of scores are between 46 and 54?

Answer 1

A standardized test is designed so that scores have a mean of 50 and a standard deviation of 4. What percent of scores are between 42 and 58?

Explanation:

about 95.4%

Answer 2

68.3%

Explanation:

Using the relation :

Zscore = (x - Mean) / standard deviation

For, x between 46 and 54

Zscore = ((54 - 50) / 4) - ((46 - 50) / 4)

P(Z < 4/4) - P(Z < -4/4)

P(Z < 1) - P(Z <-1)

0.84134 - 0.15866

= 0.68268

= 0.68268 * 100%

= 68.3%