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RenB
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RenB
Set M consists of 100 numbers, with the standard deviation of 10 and the mean of 45. Set N consists of 4 numbers. If all of the numbers in set N are added to set M, will the combined set have a standard deviation greater than 10?

1. The range of set N is 0
2. The sum of the numbers in set N is 180


Hi, In this question Shouldn't D be the answer?
As Statement 1 is sufficient on its own since Range is 0 we know that largest and smallest term are equal which means all terms are equal.SD will be zero and on combining both M and N, SD will not be more than 10.

Statement 2 is sufficient on its own as Mean is 45(180/45) and on combining M and N the mean will decrease the SD of the combined set and SD is not greater than 10.

I believe answer should be D

If Im wrong please let me know
Thanks!
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RenB
Set M consists of 100 numbers, with the standard deviation of 10 and the mean of 45. Set N consists of 4 numbers. If all of the numbers in set N are added to set M, will the combined set have a standard deviation greater than 10?

1. The range of set N is 0
2. The sum of the numbers in set N is 180


Hi, In this question Shouldn't D be the answer?
As Statement 1 is sufficient on its own since Range is 0 we know that largest and smallest term are equal which means all terms are equal.SD will be zero and on combining both M and N, SD will not be more than 10.

Statement 2 is sufficient on its own as Mean is 45(180/45) and on combining M and N the mean will decrease the SD of the combined set and SD is not greater than 10.

I believe answer should be D

If Im wrong please let me know
Thanks!

Yes, you are wrong.

The standard deviation of a set shows how much variation there is from the mean, how widespread a given set is. So, a low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.

From Statement 1, if every number in set N is 45, then the standard deviation of the combined set will decrease. However, if each number is 1,000,000, the combined set's standard deviation will increase.

Similarly, for Statement 2, if every number in set N is 45, the standard deviation of the combined set will decrease. But if the numbers are -1,000,000, -1,000,000, 1,000,000, and 1,000,180, the combined set's standard deviation will increase.
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