Estimation and Confidence Intervals

Flashcards to review key concepts related to estimation and confidence intervals.

What is a point estimate?

A point estimate is the statistic computed from sample information used to estimate the population parameter.

What is a confidence interval?

A confidence interval is a range of values constructed from sample data so that the population parameter is likely to occur within that range at a specified probability.

What factors determine the width of a confidence interval?

The width of a confidence interval is determined by sample size, variability in the population, and the desired level of confidence.

When do we use the z distribution?

We use the z distribution if the population standard deviation is known or if the sample size is 30 or more.

What is the t distribution?

The t distribution is a family of distributions that is continuous, bell-shaped, and used when the population standard deviation is unknown.

What is the formula for a confidence interval when the population standard deviation is known?

The formula is: sample mean ± z-value × (population standard deviation / √n).

What is a necessary condition to construct a confidence interval for a population proportion?

Both np and n(1-p) should be greater than or equal to 5.

What adjustment is needed for finite populations in the confidence interval calculations?

We need to apply the finite population correction factor (FPC) when the ratio of sample size to population size is significant.

What are the three factors affecting sample size determination?

The degree of confidence selected, the maximum allowable error, and the population standard deviation.

How do you compute the confidence interval for a proportion?

First, calculate the sample proportion, then apply the formula: sample proportion ± z-value × √[(p(1-p)/n)].