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In both rural and urban areas of country G, the average
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09 Dec 2017, 18:23
09 Dec 2017, 18:23
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60% (02:11) correct
39% (03:08) wrong based on 23 sessions
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In both rural and urban areas of country G, the average annual number of holidays taken by citizens is 8, and the annual number of holidays follows a normal distribution. In rural areas, 2% of the citizens take more than 12 holidays per year. In urban areas, 2% of the citizens take more than 16 holidays per year. How much greater is the standard deviation of the annual number of holidays taken by urban citizens than that of rural citizens?
Drill 2
Question: 11
Page: 526
Question: 11
Page: 526
Show: :: OA
2
Re: In both rural and urban areas of country G, the average
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29 Dec 2017, 14:08
29 Dec 2017, 14:08
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Expert Reply
Explanation
Draw two bell curves: one for rural areas, and one for urban areas. The three standard deviations above the mean each represent 34%, 14% and 2% of the population, respectively.
The mean in both cases is 8. In rural areas, 2% of the citizens take more than 12 holidays a year, so 12 is two standard deviations above 8; the standard deviation is thus the difference between 8 and 12 divided by 2, or 2. In urban areas, similarly, the standard deviation is 16 – 8 divided by 2, or 4.
The difference between the two standard deviations is thus 4 – 2 = 2.
Draw two bell curves: one for rural areas, and one for urban areas. The three standard deviations above the mean each represent 34%, 14% and 2% of the population, respectively.
The mean in both cases is 8. In rural areas, 2% of the citizens take more than 12 holidays a year, so 12 is two standard deviations above 8; the standard deviation is thus the difference between 8 and 12 divided by 2, or 2. In urban areas, similarly, the standard deviation is 16 – 8 divided by 2, or 4.
The difference between the two standard deviations is thus 4 – 2 = 2.
Re: In both rural and urban areas of country G, the average
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31 Aug 2021, 07:07
31 Aug 2021, 07:07
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