|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
02 Feb 2020, 04:38
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
65% (01:24) correct
35%
(01:15)
wrong
based on 153
sessions
History
Date
Time
Result
Not Attempted Yet
A data set has a mean of 10 and standard deviation of 3. If 4 is subtracted from to twice each data value, the new set has
a. a mean of 20 and a standard deviation of -1
b. a mean of 20 and a standard deviation of 3
c. a mean of 16 and a standard deviation of 6
d. a mean of 16 and a standard deviation of 3
e. a mean of 16 and a standard deviation of -1
a. a mean of 20 and a standard deviation of -1
b. a mean of 20 and a standard deviation of 3
c. a mean of 16 and a standard deviation of 6
d. a mean of 16 and a standard deviation of 3
e. a mean of 16 and a standard deviation of -1
03 Feb 2020, 05:08
Kudos
Bookmarks
kapil1
Solution:
- • Here, we will use the conceptual knowledge of these subjects.
• We know that when we multiply all the elements of a set by a number k, then the mean and standard deviation of the new set is also multiplied by k.
• If we subtract or add a number to all the elements of a set, then that number is also subtracted or added to the mean of the new set, but it does not affect the standard deviation of the set.
- • Each element is multiplied by \(2,\) then
- o Mean = \(10*2 = 20\)
o Standard deviation =\(2*3= 6\)
- o Mean = \(20 – 4 = 16\)
o Standard deviation = \(6\)
03 Feb 2020, 05:32
Kudos
Bookmarks
kapil1
If a data set \({a, b, c, ...}\) has mean = \(m\); median = \(d\); range = \(r\); standard deviation = \(s\), then:
The data set \({x*a + y, x*b + y, x*c + y, ...}\) will have: mean = \(x*a + y\); median = \(x*d + y\); range = \(x*r\); and standard deviation = \(x*s\)
In the above question, for every element \(a\) in the original set, the corresponding element in the new set is \(2a - 4\)
Initial mean = 10, standard deviation = 3
Thus, new mean = 2 * 10 - 4 = 16; new standard deviation = 2 * 3 = 6
Answer C
