- CFA Exams
- CFA Level I Exam
- Topic 1. Quantitative Methods
- Learning Module 7. Estimation and Inference
- Subject 1. Sampling Methods

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**CFA Practice Question**

Which of the following statements is (are) incorrect?

II. The sum of the squared sampling errors is always 0.0.

III. Given any sample, the variance of the sample mean is always less than the variance of the population.

IV. Sampling means are always random variables.

I. The mean of the sampling distribution is always equal to the mean of the population.

II. The sum of the squared sampling errors is always 0.0.

III. Given any sample, the variance of the sample mean is always less than the variance of the population.

IV. Sampling means are always random variables.

Correct Answer: II only

The statement that the sum of the squared sampling errors is always 0.0 is incorrect; the sum of the squared sampling errors is positive and the sum of the sampling errors is always 0.0.

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**User Contributed Comments**
14

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

Nikita |
How can you say the first statement is correct? |

kamin |
bcz sampling selected from all population |

cp24 |
If it is correct, then why is there such a thing as sampling error for means? |

thinkit |
It is correct. The means are equal, although it could be different every time you get a sample |

thekapila |
Guys it is correct, It talks about the mean of the sampling distribution and not the mean of sample. Mean of distribution is = population mean |

bobert |
There is a sampling error for means for individual samples compared to the population. |

kamil77 |
Why is the third one correct? |

Yurik74 |
kamil77 - my guess is that's cause we have less members in any given sample than in total population. |

Sophorior |
for 3): check the central limit theorem |

cleopatraliao |
@Yurik74 ur wrong...it's becuz the central limit theorem states that the variance of the sample mean=variance of the population/n, where n is the sample size. that's why III is correct:) |

EminYus |
i don't even remember the central limit theorem at this point..i'm trying to get through the material before a massive review |

johntan1979 |
n-1 |

gill15 |
has nothing to do with n - 1....you're confusing the stats. standard deviation of the MEAN = Std deviation of pop / root n then just think of it mathematically. |

pranubal |
what about the balance 3 answers, Is it all right |