Confidence Intervals
Confidence interval (CI) refers to a range of values within which statisticians believe the actual value of a certain population parameter lies. It is different from from a point estimate which is a single, specific numerical value.
Properties of an Estimator
A point estimator (PE) is a sample statistic used to estimate an unknown population parameter. It is a random variable and therefore varies from sample to sample. A good example of an estimator is the sample mean, \(x\), which helps…
Standard Error of the Sample Mean
The standard error (SE) of the sample mean refers to the standard deviation of the distribution of the sample means. It gives analysts an estimate of the variability they would expect if they were to draw multiple samples from the…
Probability and Non-Probability Sampling
A population is the total number of elements in a group while a sample is a portion of the population. Sample statistics—quantities such as sample mean that describe sample data—generalize the information about the population parameter. As such, we draw…
Economies and Diseconomies of Scales
Economies of Scale Economies of scale refer to the cost advantage brought about by an increase in the output of a product. Economies of scale arise due to the inverse relationship between the per-unit fixed cost and the quantity produced…
