- CFA Exams
- CFA Level I Exam
- Study Session 3. Quantitative Methods (2)
- Reading 10. Sampling and Estimation
- Subject 6. Confidence Intervals for the Population Mean

###
**CFA Practice Question**

A survey of 144 retail stores revealed that a particular brand and model of TV retails for $375 with a standard deviation of $20.

If 95% and 98% confidence intervals are developed to estimate the true cost of the TV, what difference would they have?

A. interval widths

B. both interval widths and z-variates

C. z-variates

**Explanation:**The interval widths and the z-variates differ according to the rule chosen. The standard error is the same regardless.

###
**User Contributed Comments**
2

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

smackboyg |
What is a z-variate? I cannot find a reference? |

GBolt93 |
I'm assuming it means z-value you'd use in calculating the interval. i.e. 1.96 for 95% and 2.33 for 98% |