68 % is about one standard deviation - so there score would be between 64 and 80 (72 +/- 8)
about 25
There are approximately 16.4% of students who score below 66 on the exam.
It is the sample mean age of 21.7.
The null hypothesis could be that the 40 students are a sample from the same (or similar) population.
i y=use Z-test
about 25
There are approximately 16.4% of students who score below 66 on the exam.
The expected number is 500.
Standard deviation is 0.
To see how wide spread the results are. If the average (mean) grade for a certain test is 60 percent and the standard deviation is 30, then about half of the students are not studying. But if the mean is 60 and the standard deviation is 5 then the teacher is doing something wrong.
The sample size is likely to be too small.
It is the sample mean age of 21.7.
The null hypothesis could be that the 40 students are a sample from the same (or similar) population.
Not possible to tell you without knowing how many students' there are, and what distribution you wish to use (i.e normal distribution, t-distribution etc...)
i y=use Z-test
(x-400)/100=1.882 x=588.2
0.9699