FACT OR BLUFF

The shape of a normal curve is symmetrical.

If o is unknown, the sample standard deviation s is used.

An interval estimate for a parameter is a range of values that may or may not contain the true and fixed parameter value.

The confidence coefficients for a 95% confidence interval is ±2.58.

The Central Limit Theorem states that as sample size increases, the shape of the distribution approximates the normal curve.

When the confidence level is 90%, a=0.01.

A point estimate of a population parameter is obtained from a sample.

An interval estimate is a range of values.

All confidence levels have the same confidence coefficients.

A confidence level is expressed as a fraction.