Points estimators vs. Confidence interval (CI)

Point estimators
Use single(sample) values to estimate population paramenters

Confidence interval
Estimate range of value within which the actual parameters will lie, given the probability of 1-α. (1- α) is the degree of confidence.

Desirable properties of an estimate

• Lack of bias, i.e. expected value of estimator = true value of population parameter)
• Efficiency, i.e. low variance
• Consistency, i.e. accuracy must increase with sample size
  

Construct Confidence Intervals
The general structure for a (1 – α) confidence interval is given by:
CI= Point estimate ± Reliability factor x Standard error.