Source: GMAT Prep
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
The OA is A.
The variable x takes on integer values between 1 and 7
This topic has expert replies
-
- Moderator
- Posts: 2212
- Joined: Sun Oct 15, 2017 1:50 pm
- Followed by:6 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi All,
We're told that the variable X takes on integer values between 1 and 7 inclusive as shown above (meaning that out of a total of 15 values, there are three 1s, one 2, three 3s, one 4, etc.). We're asked for the probability that the absolute value of the DIFFERENCE between the MEAN (re: 4) and a randomly chosen value of X will be GREATER than 3/2. While this question looks a bit 'thick', it's based on some basic Probability math and some Arithmetic.
To start, for the DIFFERENCE between 4 and a value in the list to be GREATER than 3/2, the value of X would have to be 1, 2, 6 or 7 (for example, 4 - 1 = 3 and 6 - 4 = 2).
Based on the frequencies, we know that there are three 1s, one 2, one 6 and three 7s. That's a total of 8 values out of the 15 total values.
Final Answer: A
GMAT assassins aren't born, they're made,
Rich
We're told that the variable X takes on integer values between 1 and 7 inclusive as shown above (meaning that out of a total of 15 values, there are three 1s, one 2, three 3s, one 4, etc.). We're asked for the probability that the absolute value of the DIFFERENCE between the MEAN (re: 4) and a randomly chosen value of X will be GREATER than 3/2. While this question looks a bit 'thick', it's based on some basic Probability math and some Arithmetic.
To start, for the DIFFERENCE between 4 and a value in the list to be GREATER than 3/2, the value of X would have to be 1, 2, 6 or 7 (for example, 4 - 1 = 3 and 6 - 4 = 2).
Based on the frequencies, we know that there are three 1s, one 2, one 6 and three 7s. That's a total of 8 values out of the 15 total values.
Final Answer: A
GMAT assassins aren't born, they're made,
Rich
GMAT/MBA Expert
- Jeff@TargetTestPrep
- GMAT Instructor
- Posts: 1462
- Joined: Thu Apr 09, 2015 9:34 am
- Location: New York, NY
- Thanked: 39 times
- Followed by:22 members
The only values of x that give us |x - 4| > 3/2 are 1, 2, 6, and 7. Since we have a total of 3 + 1 + 3 + 1 + 3 + 1 + 3 = 15 values in the list and a total of 3 + 1 + 1 + 3 = 8 values that can be x, the probability is 8/15.BTGmoderatorLU wrote:Source: GMAT Prep
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
Answer: A
Jeffrey Miller
Head of GMAT Instruction
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews