Statistical Methods

3.2.Terminology

Unit 3 - Estimation

3.2.Basic Terminology

• Population: It is the totality of individuals in a statistical investigation. For example in the study of knowing mean fish catch per boat in a landing centre, fish catches of all boats operating in the centre constitute statistical population. A study on the fish catches of all boats is called census survey.
• Sample: A few representative selection of individuals form a population. For example in the study of knowing mean fish catch per boat in a landing centre, a few boats operating selected randomly form a population. A study on the fish catches of all selected boats is called sample survey.
• Parameter: Population mean, population standard deviation, population size etc. which are quantitative characteristic of population are called parameters.
• Statistic: Sample mean, Sample standard deviation etc. which are function of sample values are called statistic.
• Parameter space: A set of all the admissible values population parameters is called parameter space.
• Sampling distribution: The distribution of values of a statistic for all different samples of the same size is called sampling distribution of the statistic.
• Standard Error: Standard deviation of sampling distribution of the statistic is called Standard Error.
• Estimator: Statistics which is used to estimate population parameter.
• Estimate: Value or range of values used to estimate population / parameters.
• Point Estimate: A single value used to estimate population parameter.
• Interval estimates: A range of values used to estimate population parameter at a given level of confidence is called confidence interval.
• Confidence coefficient: The probability that a confidence interval contains parameter is called Confidence coefficient.
• Confidence limits: They are the limits of the confidence interval.
• Estimation: It is the process of estimating population parameter.