STAT 101 FPU Statistical Technique and Standard Deviation Questions
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.6. A population has a mean of m 5 80 and a standard
deviation of s 5 20.
a. Would a score of X 5 70 be considered an
extreme value (out in the tail) in this sample?
b. If the standard deviation were s 5 5, would a
score of X 5 70 be considered an extreme value? 8. Calculate the mean and SS (sum of squared deviations) for each of the following samples. Based on
the value for the mean, you should be able to decide
which SS formula is better to use.
Sample A: 1 4 8 5
Sample B: 3 0 9 410. For the following sample of n 5 7 scores:
8 6 5 2 6 3 5c. Compute SS, variance, and standard deviation
for the sample. (How well does your estimate
compare with the actual value of s?) 13. A population has a mean of m 5 30 and a standard
deviation of s 5 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?22. In an extensive study involving thousands of
British children, Arden and Plomin (2006) found
significantly higher variance in the intelligence
scores for males than for females. Following are
hypothetical data, similar to the results obtained
in the study. Note that the scores are not regular
IQ scores but have been standardized so that
the entire sample has a mean of M 5 10 and
a standard deviation of s 5 2.
a. Calculate the mean and the standard deviation for
the sample of n 5 8 females and for the sample of
n 5 8 males.
b. Based on the means and the standard deviations,
describe the differences in intelligence scores for
males and females.
Female9,11,10,13,8,9,11,9 Male 8,10,11,12,6,10,14,923. Within a population, the differences that exist from
one person to another are often called diversity.
Researchers comparing cognitive skills for younger adults and older adults, typically find greater
differences (greater diversity) in the older population (Morse, 1993). Following are typical data
showing problem-solving scores for two groups of
participants. Older Adults
(average age 72)
Younger Adults
(average age 31) 9 4 7 3 8 7 9 6 7 8 6 2 8 4 5 6 7 6 6 8 7 5 2 6 6 9 7 8 6 9a. Compute the mean, the variance, and the standard
deviation for each group. b. Is one group of scores noticeably more variable
(more diverse) than the other? HW #3 - Part 2Question 1Find the mode for the following variables17,1, 5, 5, 17, 17,2, 9, 6, 9,17,17Question 2Find the mode for the following variables2,12, 2, 9, 2,12, 10, 2, 6,12,12Question 3Find the median for the following variables19,3, 8, 14, 19, 19,22, 29, 32, 3,19,19Question 4Find the median for the following variables20,1, 9, 13, 20, 20,23, 30, 35, 37,20Question 5Find the mean (average) for the following set of numbers:x = 3, 6, 14, 3, 5, 9, 10, 16, 11, 9Be sure to round your answer to the nearest 2 decimal places. Question 6Find the mean (average) for the following set of numbers:x = 11, 22, 12, 24, 12, 6, 10, 9, 9, 7Be sure to round your answer to the nearest 2 decimal places. Question 7Calculate the range for the following variables2, 8, 10, 9, 4, 6, 9, 14Question 8Calculate the range for the following variables3, 24, 20, 21, 33, 24, 16, 23`Question 9Find the population standard deviation for the following values:Be sure to round your answer to the 2 nearest decimal places. 2, 9, 2, 10, 1Question 10Find the population standard deviation for the following values:Be sure to round your answer to the 2 nearest decimal places. 42, 14, 41, 31, 8