4Sample size- is the number of individuals in a sample size Sample size- is the number of individuals in a sample size. We use n to represent the sample size.Sampling Frame-a list of individuals from whom the sample is drawn.
13A convenience sample consist of the individuals who are conveniently available. EX: A radio station asks its listeners to call in their opinion regarding the use of pesticides in residential areas.
14Sample schemes that combine several sampling method are called multistage samples.
15BiasA statistic is biased if it is calculated in such a way that is systematically different from the population parameter of interest.The best defense against bias is Randomization, in which each individual is given a fair, random chance of selection.
16Voluntary response bias- Bias introduced to a sample when individuals can choose on their own whether to participate in the sample.Nonresponse bias-Bias introduced to a sample when a large fraction of those sample failed to respond.Anything in a survey design that influences responses falls under the heading of response bias.Undercoverage bias, in which some portion of the population is not sampled at all or has a smaller representation in the sample than it has in the population.
17:undercoverage, in which some portion of the population is not sampled at all or has a smaller representation in the sample than it has in the population.
18In a voluntary response sample, a large group of individuals is invited to respond, and all who do respond are counted.Voluntary response samples are almost always biased, and so conclusions drawn from them are almost always wrong.
19NotationWe typically use Greek letters to denote parameters and Latin letters to denote statistics.