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rohansherry
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I have no idea what the ques is asking and what to calculate

pls explain



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10 children SD 24 Aug 2009, 10:14
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1) Mean = (70+75+80+85+90+105+105+130+130+130)/10=100
2) mean-Standard deviation = 100-22.7=77.6
3) you have to find how many numbers are less than 77.6 (these numbers will be more than one standard deviation below the mean). There are 2 numbers less than 77.7: 70, 75.
Answer: two numbers
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10 children SD 24 Aug 2009, 10:20
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mean = 100 of this list
SD = 22.4 hence we are asked to see values betwn 100 & 77.6 (ie 100-22.4)...i get ans as 2 ( 70, 75)
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10 children SD 24 Aug 2009, 10:33
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LenaA
1) Mean = (70+75+80+85+90+105+105+130+130+130)/10=100
2) mean-Standard deviation = 100-22.7=77.6
3) you have to find how many numbers are less than 77.6 (these numbers will be more than one standard deviation below the mean). There are 2 numbers less than 77.7: 70, 75.
Answer: two numbers
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bhushan252
mean = 100 of this list
SD = 22.4 hence we are asked to see values betwn 100 & 77.6 (ie 100-22.4)...i get ans as 2 ( 70, 75)
Show more

Please explain what does this line mean "are more than one standard deviation below the mean"????


are there many SD's
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10 children SD 24 Aug 2009, 11:54
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rohansherry
LenaA
1) Mean = (70+75+80+85+90+105+105+130+130+130)/10=100
2) mean-Standard deviation = 100-22.7=77.6
3) you have to find how many numbers are less than 77.6 (these numbers will be more than one standard deviation below the mean). There are 2 numbers less than 77.7: 70, 75.
Answer: two numbers
bhushan252
mean = 100 of this list
SD = 22.4 hence we are asked to see values betwn 100 & 77.6 (ie 100-22.4)...i get ans as 2 ( 70, 75)

Please explain what does this line mean "are more than one standard deviation below the mean"????


are there many SD's
Show more

It means that the distance between a number and the mean should be more than 22.4. But pick only values from the left side, which are less than the mean. In other words, (mean - X)>22.4
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10 children SD 24 Aug 2009, 12:23
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Please explain what does this line mean "are more than one standard deviation below the mean"????

You are correct rohansherry. There are many Standard Deviations.

They are the measurement of the distance from the mean.

If the child ran it in 60 seconds, we say that result is (100-60)/22.4 = 1.785 standard deviations from the mean. Note standard deviations can be above or below the mean.
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10 children SD 24 Aug 2009, 12:50
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thanks guys..........Kudos to you all



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