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

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

From 1 and question S: (30+40+50+x+25)/5 = 40
=> x = 55

=> numbers are: 25,30,40,50,55

From 2: (30+40+50+p+45)/5 = 40

=> numbers are: 10,25,30,40,50

Together, this seems to imply T has the higher standard deviation. Either way, we dont need to know exactly, just the fact that we have all the numbers to do the calc is enough

C
From 1)
Set S - 25, 30, 40, 50, 55 (calculate the last one from average)
We know the SD of Set S but donâ€™t have any idea about the SD of T

From 2)
Set T - 30, 35, 40, 45, 50.

Together
30, 40 and 50 are common members. Other elements of these sets will decide which set has greater SD.
new elements of Set S are further away from the mean (40).
SD of Set S > SD of Set T

get the mean
get the difference of the mean and each member of the set
square the differences
average the squared differences
take the square root of that average

i think GMAT rarely asks you to compute for SD. just tests the concept
_________________

For all SD questions you need to know terms in an individual series in order to be 100% sure.
Any information on mean median mode or range is not sufficient.

From st1 and given average we can determine ther terms in series one
From st2 and given average we can determie the terms in series 2

Individually 1 and 2 are not suff so eliminate A B and D