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Multilingual Demographic Dictionary, second unified edition, English volume

Significant difference

Multilingual Demographic Dictionary, second unified edition, English vol.
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Significant difference  (SIGNIFICANT difference)

A population parameter 1 is a numerical value that characterizes a population. Statistical estimation 2 is the name given to the procedure by which the values of such parameters are estimated from the sample. Such estimates are subject to sampling errors 3 and a measure of the magnitude of the sampling error is generally given by the standard error 4. Sometimes a confidence interval 5 is associated with an estimate to show the limits within which the estimated quantity may be expected to lie with a pre-determined probability. A difference between two values is referred to as a significant difference 6 when the probability that it is due to chance is less than a given value which is called the level of significance 7. Thus a difference would be significant at the 5 percent level if the probability that it could have arisen by chance is less than 0.05. In addition to sampling errors, observation errors 8 or response errors 8 also affect estimates. These errors usually include interviewer biases 9 which are systematic errors introduced by the interviewers when the basic data are collected.