# Definition of Statistics Terms

Can you help me explain these:

Systematic sample

Stratified Sample

Weighted mean

Standard deviation

Mutually exclusive events

Independent events, and

Expected value

Please include example in your response to enhance my understanding. Thanks

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#### Solution Preview

Systematic Sample:

Systematic sampling is a statistical method involving the selection of every kth element from a sampling frame, where k, the sampling interval, is calculated as: k = population size (N) / sample size (n). Using this procedure each element in the population has a known and equal probability of selection. This makes systematic sampling functionally similar to simple random sampling. It is however, much more efficient (if variance within systematic sample is more than variance of population) and much less expensive to carry out.

Stratified Sampling:

When sub-populations vary considerably, it is advantageous to sample each subpopulation (stratum) independently. Stratification is the process of grouping members of the population into relatively homogeneous subgroups before sampling. The strata should be mutually exclusive: every element in the population must be assigned to only one stratum. The ...

#### Solution Summary

The answer explains several statistics terms in great detail. An excellent response to the question asked. Overall, a great response.