In words, explain what is measured by each of the following: a. SS b. Variance c. Standard deviation
1. In words, explain what is measured by each of the
following:
a. SS
b. Variance
c. Standard deviation
2. Can SS ever have a value less than zero? Explain your
answer.
3. Is it possible to obtain a negative value for the
variance or the standard deviation?
4. What does it
deviation of zero? Describe the scores in such a
sample.
5. Explain why the formulas for sample variance and
population variance are different.
6. A population has a mean of 80 and a standard
deviation of 20.
a. Would a score of X 70 be considered an extreme
value (out in the tail) in this sample?
b. If the standard deviation were 5, would a score
of X 70 be considered an extreme value?
7. On an exam with a mean of M 78, you obtain a
score of X 84.
a. Would you prefer a standard deviation of s 2 or
s 10? (Hint: Sketch each distribution and find the
location of your score.)
b. If your score were X 72, would you prefer s 2
or s 10? Explain your answer.
8. A population has a mean of 30 and a standard
deviation of 5.
a. If 5 points were added to every score in the
population, what would be the new values for the
mean and standard deviation?
b. If every score in the population were multiplied by
3 what would be the new values for the mean and
standard deviation?
9. a. After 3 points have been added to every score in a
sample, the mean is found to be M 83 and the
standard deviation is s 8. What were the values
for the mean and standard deviation for the original
sample?
b. After every score in a sample has been multiplied
by 4, the mean is found to be M 48 and the
standard deviation is s 12. What were the values
for the mean and standard deviation for the original
sample?
10. A student was asked to compute the mean and
standard deviation for the following sample of n 5
scores: 81, 87, 89, 86, and 87. To simplify the
arithmetic, the student first subtracted 80 points from
each score to obtain a new sample consisting of 1, 7,
9, 6, and 7. The mean and standard deviation for the
new sample were then calculated to be M 6 and
s 3. What are the values of the mean and standard
deviation for the original sample?
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 1 images
