LESSON 2
ANSWER KEY AND FEEDBACK
Situation I
Construction of the table below facilitates computation of the measures of central tendency and
dispersion. Note that the observations have been listed in ascending order.
(X-u) 2
X
(X - u)
6
-4
16
6
-4
16
7
-3
9
8
-2
4
9
-1
1
11
1
1
13
3
9
13
3
9
13
3
9
14
_4
16
ΣX = 100
Σ(X - u) = 0
Σ(X-u)2 = 90
1. B Mean: = ΣX = 100 = 10
(Frame 25)
2. A Median: 9 + 11 = 20 = 10. If you did not put the data in
2
2
an ordered array, you would have obtained the wrong answer.
(Frame 29)
3. D Mode: 13 (occurs 3 times)
(Frame 31)
4. D Range = largest - smallest - 14 - 6 = 8
(Frame 34)
5. C
Standard deviation σ =
(X-u)2
=
90
=
9
=
3
N
10
(Frame 36)
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