The following table shows the probability distribution of the number of days (x) to complete a certain type of construction project by a contractor. |
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| x | f(x) |
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| 1 | 0.05 |
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| 2 | 0.20 |
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| 3 | 0.35 |
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| 4 | 0.30 |
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| 5 | 0.10 |
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3 | The probability that it will take less than 3 days to complete a randomly selected project is ______. |
a | 0.60 |
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b | 0.45 |
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c | 0.35 |
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d | 0.25 |
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4 | The standard deviation of the days to complete a project is _______. (Rounded to 2 decimal points.) |
a | 1.03 |
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b | 1.24 |
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c | 1.35 |
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d | 1.41 |
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5 | The contractor's project cost is made up of a fixed cost of $20,000, plus $2,000 for each day taken to complete the project. Expected value of total project cost is. |
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a | $25,300 |
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b | $26,400 |
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c | $27,500 |
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d | $28,600 |
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6 | In the previous question the standard deviation of total project cost is: |
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a | $22,060 |
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b | $22,828 |
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c | $2,060 |
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d | $2,828 |
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7 | If you toss a balanced coin 20 times, the probability of getting 10 tails is: f(x = 10) = _______. |
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a | 0.5000 |
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b | 0.2461 |
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c | 0.1762 |
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d | 0.1026 |
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