Office A:
22
31
21
49
26
42
42
30
28
31
39
39
Office B:
20
37
32
36
35
33
45
47
49
38
28
48
Ex. 2
Below are times obtained from a mailorder company's shipping records concerning time from receipt of order to
delivery (in days) for items from their catalogue?
3
7
10
5
14
12
6
2
9
22
25
11
5
7
12
10
22
23
14
8
5
4
7
13
27
31
13
21
6
8
3
10
19
12
11
8
Homework:
Day 1:
pg 46 – 48 problems 15
Day 2:
pg 5558 problems 812 and pg 64 – 66 problem 16
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View Full DocumentChapter 1:
Exploring Data
Section 1.2:
Describing Distributions with Numbers
Knowledge Objectives:
Students will:
Explain what is meant by a
resistant measure
.
Give two reasons why we use squared deviations rather just average deviations from the mean.
Explain what is meant by
degrees of freedom
.
Construction Objectives:
Students will be able to:
Identify situations in which the
mean
is the most appropriate measure of center and situations in which the
median
is
the most appropriate measure.
Given a data set:
Find the
quartiles
.
Find the
fivenumber summary
.
Compute the
mean
and
median
as
measures of center
.
Compute the
interquartile range
(IQR).
Use the
1.5
×
IQR
rule to identify outliers.
Compute the
standard deviation
and
variance
as measures of
spread
.
Identify situations in which the
standard deviation
is the most appropriate measure of spread and situations in which
the
interquartile range
is the most appropriate measure.
Explain the effect of a
linear transformation
of a data set on the
mean, median,
and
standard deviation
of the set.
Use numerical and graphical techniques to compare two or more data sets.
Vocabulary:
Boxplot – graphs the five number summary and any outliers
Degrees of freedom – the number of independent pieces of information that are included in your measurement
Fivenumber summary – the minimum, Q1, Median, Q3, maximum
Interquartile range (IQR) – IQR = Q3 – Q1
Linear transformation – changes the data in the form of x
new
= a + bx
Mean – the average value
Median – the middle value (in an ordered list)
Mode – the most frequent data value
Outlier– a data value that lies outside the interval [Q1 – 1.5
IQR, Q3 + 1.5
IQR]
P
th
percentile – p percent of the observations (in an ordered list) fall below at or below this number
Quartile – multiples of 25
th
percentile (Q1 – 25
th
; Q2 –50
th
or median; Q3 – 75
th
)
Range – difference between the largest and smallest observations
Resistant measure – a measure (statistic or parameter) that is not sensitive to the influence of extreme observations
Standard Deviation– the square root of the variance
Variance – the average of the squares of the deviations from the mean
Key Concepts:
Measure of
Central Tendency
Computation
Interpretation
When to use
Mean
μ = (∑x
i
) / N
x‾ = (∑x
i
) / n
Center of gravity
Data are quantitative and
frequency distribution is
roughly symmetric
Median
Arrange data in ascending
order and divide the data set
into half
Data are quantitative and
frequency distribution is
skewed
Mode
Tally data to determine most
frequent observation
Data are qualitative or the
most frequent observation is
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 Fall '12
 SonjaCox
 Histograms, Standard Deviation, AP Statistics, Bar chart

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