- 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**

In a group of 12 scores, the largest score is increased by 36 points. What effect will this have on the mean of the scores?

B. It will be increased by 3 points.

C. There is no way of knowing exactly how many points the mean will be increased by.

A. It will be increased by 12 points.

B. It will be increased by 3 points.

C. There is no way of knowing exactly how many points the mean will be increased by.

Correct Answer: B

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**User Contributed Comments**
10

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

rainatt |
(X+36)/12=X/12+3 |

rinkoo |
can anyone make it more clear??? |

AyshaAli |
to find the mean we have to find the average, hence 36 should be divided by 12 which is the no. scores |

chek |
let,the first nos are 1+2+3+...+12=78, avg=78/12=6.5, If i change 12th no 12 with more 36 i.e 48 then, 1+2+3+...+11+48= 114,avg is=114/12=9.5,incresed by 3.this is applicable for every number. |

Meka76 |
Great explanation Chek |

albert2008 |
Basically you just divide the score increase by N. In this case N = 12. I'm not a math genius so I had to plug in some other numbers to verify check's explanation. |

RCapistrano |
36/12 = 3 You can also check by picking any number and multiply that number 12 times --- 2(12) =24 24 + 36(increase)/12 = 5 24 + 36 + 36 = 8 and so on... and the change will always be 3. |

anniepass |
there are 12 scors, each one has equal weight by 1/12, then 36 * 1/12 = 3 |

rsanfo |
x+36/12 = x/12 + 36/12 = x/12 + 3. No matter what x is, the mean increases by 3. |

Konstantis |
m=x/12 , x=12*m (m: average before the increase, x the total of your scores) m+y=(x+36)/12 (Y is the increase of average) replace x with 12*m you take m+y=m+3 Y=3 |