- If scores are normally distributed with a mean of 30 and a standard deviation
of 5, what percent of the scores is: (a) greater than 30? (b) greater than
37? (c) between 28 and 34?
- (a) What are the mean and standard deviation of the standard normal distribution?
(b) What would be the mean and standard deviation of a distribution created
by multiplying the standard normal distribution by 10 and then adding 50?
- The normal distribution is defined by two parameters. What are they?
- (a) What proportion of a normal distribution is within one standard deviation
of the mean? (b) What proportion is more than 1.8 standard deviations from
the mean? (c) What proportion is between 1 and 1.5 standard deviations above
- A test is normally distributed with a mean of 40 and a standard deviation
of 7. (a) What score would be needed to be in the 85th percentile? (b) What
score would be needed to be in the 22nd percentile?
- Assume a normal distribution with a mean of 90 and a standard deviation
of 7. What limits would include the middle 65% of the cases.
- For this problem, use the scores in the identical blocks test (second in
the dataset "High_School_Sample").
Compute the mean and standard deviation. Then, compute what the 25th and 75th
percentile would be if the distribution were normal. Compare the estimates
to the actual 25th and 75th percentiles.