Download Classwork due 1/31/2017 Review

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Community College of Denver
Course: MAT135 –Statistics
Instructor: Vikki French
vikki.french@ccd.edu
______________________________________
Classwork due 1/31/2017
Review
1) n is:
a)
b)
c)
d)
the number in the population
the number in the sample
the number of non-zero observations
the range number
2) Circle the measures of central tendency
(you may have more than one):
a)
b)
c)
d)
e)
f)
g)
average
the central limit theorem
arithmetic mean
median
mode
midrange
standard deviation
3) x̄ is your sample estimate of μ:
a) true
b) false
4) n is your sample estimate of N:
a) true
b) false
Descriptive Statistics – Variability
5) For which of these two sets of data
would the mean be a better descriptor?
6) For which of these two sets of data
would the mean be a better descriptor?
mean ≡
sum of observations)
# observations
median => the middle value
in the ordered list
(for an even # of observations)
the median is the mean of the two
middle values in the list
mode ≡ the most common
observation
(may be more than one)
For the data set: 1 1 2 2 3 3
7) What is the range?
8) What is the mean (x̄)?
9) What are the deviations (obs – x̄)? (you will have 6 numbers)
10) What are the squared deviations? (you will have 6 numbers)
11) What is the sum of the squared deviations? (you will have 1 number)
12a) What is n-1?
12b) What is the variance (s2)?
13) What is the standard deviation (s or std)?
So what the heck is this “standard deviation” anyway? What does it mean?
Suppose we looked at a sample of two pizza delivery driver times.
They had the same mean (15 minutes),
but Amanda’s standard deviation of delivery times = 2.6 minutes
while Bethany’s standard deviation of delivery times = 8.4 minutes.
14) Who should get the raise? Why? (Remember they had the same mean delivery time,
but different standard deviations)
15) What are the advantages of having a data set that has a small standard deviation?
16) Is the mode affected by an outlier?
17) Is the median affected by an outlier?
18) Is the mean affected by an outlier?
19) Is the range affected by an outlier?
20) Is the standard deviation “s” affected by an outlier?
21) What advantages does the standard deviation have over the range?