- CFA Exams
- 2021 CFA Level I Exam
- Study Session 2. Quantitative Methods (1)
- Reading 7. Statistical Concepts and Market Returns
- Subject 4. Measures of Center Tendency

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**CFA Practice Question**

If a teacher computes the mean for a set of test scores and then subtracts this mean from each score, the sum of the resulting set of different scores will equal ______.

B. the mean

C. n times the mean

A. zero

B. the mean

C. n times the mean

Correct Answer: A

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**User Contributed Comments**
5

User |
Comment |
---|---|

udhay |
Can some one explain this please. |

VikramJ |
Not sure why this is the case either. But I just made up an example. Let's say your set is [1,2] with mean 1.5. Subtract 1.5 from each value and you have -0.5 and 0.5 which equal 0.. |

2014 |
Sum of deviations from mean is zero. (4,5,6) 15/3 = 5 4-5= -1 5-5=0 6-6=1 +1-1= 0 |

msk500 |
Good explanation, 2014 |

cosmos1994 |
1,2,3 mean is 2 new set -1,0,1 >> -1+0+1=0 |