GMAT Exam  >  GMAT Questions  >  S is standard deviation of a, b, and c, if a ... Start Learning for Free
S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?
  • a)
    S
  • b)
    S*C
  • c)
    S*3C
  • d)
    S+C
  • e)
    S+3C
Correct answer is option 'A'. Can you explain this answer?
Verified Answer
S is standard deviation of a, b, and c, if a constant C is added to al...
Finding standard deviation of {a, b, c}
Step 1
Let Mean of {a,b,c} = {a + b + c}/3 = M
Step 2
Distances of each point from the mean:
  • a-M
  • b-M
  • c-M
Step 3
Squared Distance from Mean
  • = (a -M)2 + (b-M)2 + (c -M)2
Step 4
  • Average = {(a -M)2 + (b-M)2 + (c -M)2}  /3
Step 5
  • Standard Deviation = √ {(a -M)2 + (b-M)2 + (c -M)2}  /√ 3 = S
Finding standard deviation of {a+C, b+C, c+C}
Remember: The standard deviation of a set remains the same even if a constant is added to all the elements of the set
So the standard deviation of this set should be S.
Alternatively you can calculate the standard deviation of this set as shown below by following same step by step method.
Step 1
Mean of {a+C, b+C, c+C}  = (a + b + c )/3 + C = M + C
Step 2
Distances of each point from the mean:
  • a+C – M-C = a – M
  • b+C -M-C = b-M
  • c+C – M-C = c-M
Step 3
Squared Distance from Mean
  • = (a -M)2 + (b-M)2 + (c -M)2
Step 4
  • Average = {(a -M)2 + (b-M)2 + (c -M)2}  /3
Step 5
Standard Deviation = √ {(a -M)2 + (b-M)2 + (c -M)2}  /√ 3 = S
Answer: Option (A)
View all questions of this test
Most Upvoted Answer
S is standard deviation of a, b, and c, if a constant C is added to al...
Explanation:
To understand why the new standard deviation will be the same as the original standard deviation, we need to understand the concept of standard deviation and how it is affected by adding a constant to each data point.

Standard Deviation:
The standard deviation measures the spread or dispersion of a set of data points. It tells us how much the data points deviate from the mean. A higher standard deviation indicates a greater spread of data points, while a lower standard deviation indicates a smaller spread.

Effects of Adding a Constant to Data Points:
When a constant is added to each data point, it does not affect the spread or dispersion of the data points. It simply shifts the entire distribution by the same amount. This means that the new data points will have the same relative distances from each other as the original data points.

Effect on Standard Deviation:
Since the standard deviation measures the spread or dispersion of the data points, adding a constant to each data point does not change the spread. The new standard deviation will be the same as the original standard deviation.

Proof:
Let's assume the original standard deviation is S. Adding the constant C to each data point will result in new data points: a+C, b+C, and c+C.

To calculate the new standard deviation, we need to calculate the variance of the new data points:

Variance = ((a+C - (a+b+c+C)/3)^2 + (b+C - (a+b+c+C)/3)^2 + (c+C - (a+b+c+C)/3)^2) / 3

Expanding and simplifying the above expression, we get:

Variance = ((a - (a+b+c)/3)^2 + (b - (a+b+c)/3)^2 + (c - (a+b+c)/3)^2) / 3

This is the same as the original variance, which is equal to S^2.

Therefore, the new standard deviation is equal to the original standard deviation S.

Hence, the correct answer is option 'A'. The new standard deviation will be S.
Attention GMAT Students!
To make sure you are not studying endlessly, EduRev has designed GMAT study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in GMAT.
Explore Courses for GMAT exam

Top Courses for GMAT

S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer?
Question Description
S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? for GMAT 2024 is part of GMAT preparation. The Question and answers have been prepared according to the GMAT exam syllabus. Information about S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for GMAT 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer?.
Solutions for S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for GMAT. Download more important topics, notes, lectures and mock test series for GMAT Exam by signing up for free.
Here you can find the meaning of S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer?, a detailed solution for S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? has been provided alongside types of S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice S is standard deviation of a, b, and c, if a constant C is added to all the three digits, the new standard deviation will be?a)Sb)S*Cc)S*3Cd)S+Ce)S+3CCorrect answer is option 'A'. Can you explain this answer? tests, examples and also practice GMAT tests.
Explore Courses for GMAT exam

Top Courses for GMAT

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev