Composite scores on the ACT test for the 2015 high school graduating class had mean21.0

21.0and standard deviation5.5

5.5. In all,1,924,436

1,924,436students in this class took the test. Of these,205,584

205,584had scores higher than28

28, and another60,551

60,551had scores exactly28

28. ACT scores are always whole numbers. The exactly Normal(21.0,5.5)

N(21.0,5.5)distribution can include any value, not just whole numbers. What is more, there is no area exactly above28

28under the smooth Normal curve. So ACT scores can be only approximately Normal.

(a) Find the percent of 2015 ACT scores greater than28

28. (Enter your answer rounded to two decimal places.)

percent:

%

(b) Find the percent of 2015 ACT scores greater than or equal to28

28. (Enter your answer rounded to two decimal places.)

percent:

%

(c) UsingTable A, find the percent of observations that are greater than28

28using the(21.0,5.5)

N(21.0,5.5)distribution. The percent greater than or equal to28

28is the same, because there is no area exactly above28

28. (Enter your answer rounded to two decimal places.)

percent: