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The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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Updated on: 09 Jan 2013, 03:43
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X frequency 1 3 2 1 3 3 4 1 5 3 6 1 7 3 The variable x takes on integer values between 1 and 7 inclusive as shown above. What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2? A) 8/15 B) 4/7 C) 4/5 D) 6/7 E) 8/7 Attachment:
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Originally posted by fozzzy on 08 Jan 2013, 21:25.
Last edited by fozzzy on 09 Jan 2013, 03:43, edited 1 time in total.




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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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08 Jan 2013, 22:26
The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7 The question basically asks for the probability of choosing 1,2,6 or 7. = 8/15
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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08 Jan 2013, 22:47
MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set?



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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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08 Jan 2013, 22:58
bhavinshah5685 wrote: MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7.
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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09 Jan 2013, 20:47
MacFauz wrote: bhavinshah5685 wrote: MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7. Hi MacFauz, I guess answer is correct but the solution seems to be different to me. Pls correct me! given absolute difference is \(4X >1.5\) so \(1.5> 4X >1.5\) solving this \(2.5 < X < 6.5\) This gives range from 3,3,3,4,5,5,5,6 Anyways, answer will be 8/15. Actually i did this wrong. On seeing ur solution i got it
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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09 Jan 2013, 21:27
shanmugamgsn wrote: MacFauz wrote: bhavinshah5685 wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15
Hi Can you please explain in detail?
how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7. Hi MacFauz, I guess answer is correct but the solution seems to be different to me. Pls correct me! given absolute difference is \(4X >1.5\) so 1.5> 4X >1.5solving this \(2.5 < X < 6.5\) This gives range from 3,3,3,4,5,5,5,6 Anyways, answer will be 8/15. Actually i did this wrong. On seeing ur solution i got it The step in red is incorrect. You should note that the least value that 4X can take is 0. So, it can never be less than 1.5. The inequality should actually be X<2.5 or X>5.5.
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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09 Jan 2013, 22:53
Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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09 Jan 2013, 22:58
shanmugamgsn wrote: Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain I guess I wasn't clear. What I meant to say was that a modulus value cannot be negative. Of course in this question, we want only values for which 4X>1.5. The range that you have given (1.5> 4X >1.5) is not a valid one. A number cannot be both greater than 1.5 and lesser than 1.5. Rather the interval should be 1.5 < 4X OR 4X < 1.5
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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10 Jan 2013, 20:05
MacFauz wrote: shanmugamgsn wrote: Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain I guess I wasn't clear. What I meant to say was that a modulus value cannot be negative. Of course in this question, we want only values for which 4X>1.5. The range that you have given (1.5> 4X >1.5) is not a valid one. A number cannot be both greater than 1.5 and lesser than 1.5. Rather the interval should be 1.5 < 4X OR 4X < 1.5 Thanks MacFauz... ya i got my mistake in Inequalities. Thanks dude...
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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29 Mar 2013, 00:51
x has values between 1 and 7 so \(4x>\frac{3}{2}\)= 41=3>3/242=2>3/243=1>3/2 44=0>3/2 45=1>3/246=2>3/247=3>3/2The value that respect 4x>3/2 are 1,2,6,7 that have a frequency of 3,1,1,3 so \(3+1+1+3\) = total frequencies of "right" events, and this will be our numerator. Our denominator will be the tot number of combinations = \(3+1+3+1+3+1+3= 15.\) Answer \(\frac{8}{15}\)
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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18 Jul 2013, 03:44
I have a question regarding the denominator 15 : why do we take into consideration the value 4 since it occurs only once and we're looking for the the difference between this value and the others. I had the answer wrong because I assumed the denominator was 14  could someone try to explain?



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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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18 Jul 2013, 07:50
aa81 wrote: I have a question regarding the denominator 15 : why do we take into consideration the value 4 since it occurs only once and we're looking for the the difference between this value and the others. I had the answer wrong because I assumed the denominator was 14  could someone try to explain? The question states What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2? you get 15 when you add the frequency ( 3+1+3 etc) The set is The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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18 Jul 2013, 08:41
fozzzy wrote: X frequency 1 3 2 1 3 3 4 1 5 3 6 1 7 3
The variable x takes on integer values between 1 and 7 inclusive as shown above. What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2?
A) 8/15 B) 4/7 C) 4/5 D) 6/7 E) 8/7 How can the probability of doing something be 3/2? How can the probability of doing something be greater than 1? I don't understand what y'all are calculating.
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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18 Jul 2013, 09:29
knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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18 Jul 2013, 09:35
fozzzy wrote: knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333 Then the answer should be 0 since the answer will be below 3/2. 3/2 is higher than 1 and the answer is below 1. Therefore, since the answer is certainly below 1 and 1 is below 3/2, then the answer is 0. And 0 is not one of the answer choices. Summary: the question is faulty.
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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21 Jul 2013, 02:41
knightofdelta wrote: fozzzy wrote: knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333 Then the answer should be 0 since the answer will be below 3/2. 3/2 is higher than 1 and the answer is below 1. Therefore, since the answer is certainly below 1 and 1 is below 3/2, then the answer is 0. And 0 is not one of the answer choices. Summary: the question is faulty. Please read the question carefully. The question asks "what is the probability that SOME VALUE will be greater than 3/2?" not "is the probability of SOME EVENT greater than 3/2?"
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Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
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03 Sep 2015, 18:21
Hi,
Can someone explain why we have considered frequencies while the stem asks us about the value of X?
I mean, the probability of abs (4X) >1.5 , then what values of X can be considered ?
Or did i miss something?



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