1 standard deviation in this case is 9.7 to 10.3 six numbers are within this range so the answer is 6/8 * 100 = 75%
Need a detailed solution: Thanks
- There are these 8 numbers in a set 9.4,9.9,9.9,9.9,10.0,10.2,10.2,10.5 The mean and standard deviation of the 8 numbers are 10.0 and 0.3 respectively, what percent of the 8 numbers are within 1 standard deviation of the mean?
The question says "The mean and standard deviation of the 8 numbers are 10.0 and 0.3 respectively" so:
mean = 10
sd = 0.3
"one standard deviation" = 1*(sd) = 0.3.
two standard deviations would be 2*(sd) = 0.6, etc.
A number that is within SD away from the mean could be greater or less than the mean -- in this case, it could be either of the following:
greater than 10 - 0.3 = 9.7
less than 10 + 0.3 = 10.3
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The fourth grade at school X is made up of 300 students who have a total weight of 21,600 pounds.
If the weight of these four graders has a normal distribution and standard deviation equals 12 pounds, approximately what percentage of the fourth graders weighs more than 84 pounds?
need detailed explanation,,and also want to know what are bell curve questions and how it will relate with standard deviaion. thanks
Where did you get this question? My believe is that GMAT will not be asking questions like this....
Mean = 21600/300 = 72
Mean + 1sigma (std dev) = 72 + 12 = 84
+/- 1<sigma> covers 68.2% (34.1% + 34.1%) of the normal distribution. Therefore, remain distribution of data 100% - 68.2% = 31.8%.
Since we care only about data points above 84 lbs => 31.8 / 2 = 15.9% = 16%
What's the answer?
PERMUTATION AND COMBINATION
A teacher prepares a test. She gives 5 objective type question out of which 4 have to be answered. Find the total ways in which they can be answered if the first 2 questions have 3 choice and last 3 have 4 choice.
help me with this question,,is there any specific formula applied in thes type of questions???
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