Given that the mean of Set A is 10, what is the range of two

Question

Given that the mean of Set A is 10, what is the range of two standard deviations above and below the mean?

(1) One standard deviation above and below the mean ranges from 7 to 13.

(2) The median of set A is 11.

watwazdaquestion · Accepted Answer

1. standard deviation = 3 since mean = 10... 3 units below and 3 units above. can calculate range of 2 standard deviations above and below mean by: 10-6 = 4 and 10+6 = 16... range of 2 standard deviations above and below mean = (4, 16)
2. gives no information on standard deviation. insufficient.

answer is A

Bunuel · Answer

Similar questions to practice: 70-75-80-85-90-105-105-130-130-130-the-list-shown-consist-of-100361.html the-standard-deviation-of-a-normal-distribution-of-data-is-99221.html for-a-certain-exam-a-score-of-58-was-2-standard-deviations-b-128661.html Hope it helps.

Sachin9 · Answer

how did u calculate the standard deviation to be 3?

Kris01 · Answer

1. says that 1 standard deviation above and below the mean ranges from 7 to 13. Calculate the range. Range=6.

Now, standard deviation for a set is constant. Let us draw a number line.

---------|----------------|---------------|------------------ 
 -m mean +m

In this line segment, mean is at the center and the distance between 2 equal points -m and +m from mean is 6. These two points are equidistant as they are mentioned to be one standard deviation above and below the mean. Hence, the range of values between them=2m
2m=6
Hence, m=3

Hope this clarifies any doubts!

neeti1813 · Answer

The solutions provided above are still not clear. Could someone please make an attempt to give a detailed solution as I am very weak at mean median mode problems :roll:

WoundedTiger · Answer

Hi Neeti, You need to review basics. Go through the link below and then comeback to the question to see if you can answer it math-standard-deviation-87905.html

rhine29388 · Answer

Statement 1 states that 7 is one standard deviation below the mean and 13 is one standard deviation above the mean , clearly we can calculate range of two standard deviations above and below the mean which would be 
lower range below mean - 4 
upper range above mean - 16 
So clearly sufficient
Statement 2 states the median of the set which is of no use in standard deviation calculations so clearly inufficient
correct answer - A

ScottTargetTestPrep · Answer

We are given that the mean of set A is 10, and we need to determine the range of two standard deviations above and below the mean. If we let s = the standard deviation, we need to calculate:

10 + 2s - (10 - 2s)

If we simplify this expression, we have 4s. That is, if we can determine the standard deviation, we can determine the value of 4s.

Statement One Alone:

One standard deviation above and below the mean ranges from 7 to 13.

Using the information in statement one, we can say that 10 - s = 7 and 10 + s = 13. Solving s in either equation, we have s = 3. Thus, 4s = 12.

Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E.

Statement Two Alone:

The median of set A is 11.

Knowing the median of the set is not enough information to determine the standard deviation. Statement two alone is not sufficient to answer the question.

Answer: A

debtanuB · Answer

Actually its a simple question if you understand what exactly it is trying to tell you?? Mean(m)=10 (Given) ; Asked=Range of two std. dev. above & below mean ,i.e, (m-2d) & (m+2d) ?? From, (1) its clear (m-d) & (m+d) are 7 & 10 respectively ; Therefore, (m-d)=7 =>d=10-7=3 =>m-2d & m+2d are (10-2x3) & (10+2x3) OR 4 & 16 respectively; Hence, (1) is SUFFICIENT ; From, (2) we get no clue about std. dev. as it talks about median only ; Hence, (2) is INSUFFICIENT ; Thus, answer is option A ; All the best !!

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Given that the mean of Set A is 10, what is the range of two

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Given that the mean of Set A is 10, what is the range of two

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