An investment bank is interested in monitoring the weekly amount (in millions of dollars) invested in volatile stocks so as to maintain a stable rate of return on a selected fund. Table shows 25 consecutive weeks of the amount invested ($M) in the fund.
Construct appropriate control charts and comment on the stability of investment. Revise the chart, if necessary, assuming special causes for out-of-control points. What is your estimate of the standard deviation of the weekly amount invested?
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Table: Weekly investment in Volatile Stocks
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Week
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Investment(SM)
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Week
|
Investment(SM)
|
Week
|
Investment(SM)
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1
|
16.2
|
10
|
12.9
|
19
|
16.3
|
|
2
|
10.8
|
11
|
28.5
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20
|
14.2
|
|
3
|
18.9
|
12
|
23.3
|
21
|
21.5
|
|
4
|
14.4
|
13
|
20.2
|
22
|
18.6
|
|
5
|
15.7
|
14
|
19.3
|
23
|
20.9
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|
6
|
25.3
|
15
|
14.8
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24
|
22.4
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|
7
|
20.4
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16
|
18.7
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25
|
21.8
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|
8
|
22.6
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17
|
20.4
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|
9
|
17.8
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18
|
21.2
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