- CFA Exams
- CFA Exam: Level I 2021
- 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**

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread wear was found to be 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life, in miles, for the entire population of these tires?

B. (3,500/100)

C. (50,000/100)

A. 50,000

B. (3,500/100)

C. (50,000/100)

Correct Answer: A

The sample mean is a good estimate of the population mean.

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**User Contributed Comments**
5

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

8thlegend |
I spent 10 mins figuring out how to do this. Then i realized that this was the first question and wasted 10 mins of my life. |

thekid |
8thlegend---> 10minutes + the time it took you to post up your comment in regards to this "first question" lol..i'm going insane. |

Ktrain |
10 minutes + the 250 hours studying for this test |

2014 |
Sample represents population, The purpose of picking up sample serves the estimation of same results. U cannot do research on entire population of tyres. So u have selected a sample. Now, sample results u would rely to predict information. There is no choice or this is best choice to estimate |

JMORALES |
haha |