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Re: 70 75 80 85 90 105 105 130 130 130 The list shown consist of [#permalink]
04 Jan 2013, 04:53

Bunuel wrote:

mainhoon wrote:

How many of the 10 running times are more than one SD below the mean.

So then 1SD below the mean is 77.6. It asks how many of the 10 running times are more than 77.6? I just replaced the one SD below the mean by the value. There are more than 2... What am I missing?

You have a problem with wording.

WRONG reading: How many of the 10 running times are more than one SD below the mean. So more than Mean-SD.

CORRECT reading: How many of the 10 running times are more than one SDbelow the mean. So less than Mean-SD.

I am still not getting this.. Why is it less and not more.. Please elaborate .. _________________

hope is a good thing, maybe the best of things. And no good thing ever dies.

Re: 70 75 80 85 90 105 105 130 130 130 The list shown consist of [#permalink]
04 Jan 2013, 04:59

Expert's post

Sachin9 wrote:

Bunuel wrote:

mainhoon wrote:

How many of the 10 running times are more than one SD below the mean.

So then 1SD below the mean is 77.6. It asks how many of the 10 running times are more than 77.6? I just replaced the one SD below the mean by the value. There are more than 2... What am I missing?

You have a problem with wording.

WRONG reading: How many of the 10 running times are more than one SD below the mean. So more than Mean-SD.

CORRECT reading: How many of the 10 running times are more than one SDbelow the mean. So less than Mean-SD.

I am still not getting this.. Why is it less and not more.. Please elaborate ..

This is more verbal issue than math. In English the first reading is not correct while the second one is. _________________

Re: 70 75 80 85 90 105 105 130 130 130 The list shown consist of [#permalink]
19 Jun 2014, 03:49

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

Re: 70 75 80 85 90 105 105 130 130 130 The list shown consist of [#permalink]
14 Aug 2014, 11:11

How many of the 10 running times are more than one SD below the mean.?

This is a pretty mean and twisted question, especially on GMAT because only one out of ten would be able to crack it under 2 mins. To understand this question, draw or visualize the standard deviation-mean graph. Look at it this way: How many of the running times are farther than one standard deviation below the mean? Another way of looking at it is, how many values lie towards the left of one standard deviation below the mean.