Term
|
Definition
| consists of methods for organizing and summarizing information |
|
|
Term
|
Definition
| consists of methods for drawing and measuring the reliability of conclusions about a population based on information obtained from a sample of the poupulation |
|
|
Term
|
Definition
| the collection of all individuals or items under consideration in a statistical study |
|
|
Term
|
Definition
| that part of the population from which information is obtained |
|
|
Term
|
Definition
| researchers simply observe characteristics and take measurements, as in a sample survey |
|
|
Term
|
Definition
| researchers impose treatments and controls and then observe characteristics and take measurements |
|
|
Term
|
Definition
obtaining information for the entire population of interest
may be time consuming, costly, impractical, or even impossible |
|
|
Term
|
Definition
| reflects as closely as possible the relevant characteristics of the population under consideration |
|
|
Term
|
Definition
| a random device--such as tossing a coin, consulting a table of random numbers, or employing a random-number generator--is used to decide which members of the population will constitute the sample instead of leaving such decisions to human judgement |
|
|
Term
|
Definition
| a sampling procedure for which each possible sample of a given size is equally likely to be the one obtained |
|
|
Term
|
Definition
| a sample obtained by simple random sampling |
|
|
Term
| simple random sampling with replacement |
|
Definition
| a member of the population can be selected more than once |
|
|
Term
| simple random sampling without replacement |
|
Definition
| a member of the population can be selected at most once |
|
|
Term
|
Definition
| a table of randomly chosen digits |
|
|
Term
| systematic random sampling procedure |
|
Definition
1. divide the population size by the sample size and round the result down to the nearest whole number, m
2. Use a random-number table or a similar device to obtain a number, k, between 1 and m
3. Select for the sample those members of the population that are numbered k, k+m, k+2m,... |
|
|
Term
| cluster sampling procedure |
|
Definition
1. divide the population into groups (clusters)
2. obtain a simple random sample of the clusters
3. use all the members of the clusters obtained in step 2 as the sample |
|
|
Term
|
Definition
| the population is first divided into strata, and then sampling is done from each stratum. Ideally, the members of each stratum should be homogenous relative to the characteristic under consideration. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the strata are sampled in proportion to their size |
|
|
Term
| stratified random sampling with proportional allocation procedure |
|
Definition
1. Divide the population into subpopulations (strata)
2. From each stratum, obtain a simple random sample of size proportional to the size of the stratum; that is, the sample size for a stratum equals the total sample size times the stratum size divided by the population size
3. Use all the members obtained in Step 2 as the sample |
|
|
Term
|
Definition
used in large-scale surveys
combines one or more of simple random sampling, systematic random sampling, cluster sampling, and stratified sampling |
|
|
Term
|
Definition
| the individuals or items on which the experiment is performed |
|
|
Term
|
Definition
| term used when the experimental units are humans |
|
|
Term
|
Definition
an experimental condition
for one-factor experiments, the treatments are othe levels of the single factor. for multifactor experiments, each treatment is a combination of levels of the factors. |
|
|
Term
Principles of Experimental Design:
Control |
|
Definition
| two or more treatments should be compared |
|
|
Term
Principles of Experimental Design:
Randomization |
|
Definition
| the experimental units should be randomly divided into groups to avoid unintentional selection bias in constituting the groups |
|
|
Term
Principles of Experimental Design:
Replication |
|
Definition
| A sufficient number of experimental units should be used to ensure that randomization creates groups that resemble each other closely and to increase the chances of detecting any differences among the treatments |
|
|
Term
|
Definition
| the group receiving the specified treatment |
|
|
Term
|
Definition
| group receiving the placebo |
|
|
Term
|
Definition
| the characteristic of the experimental outcome that is to be measured and observed |
|
|
Term
|
Definition
| a variable whose effect on the response is of interest in the experiment |
|
|
Term
|
Definition
| the possible values of a factor |
|
|
Term
| completely randomized design |
|
Definition
| all the experimental units are assigned randomly among all the treatments |
|
|
Term
|
Definition
| the experimental units are assigned randomly among all the treatments separately within each block |
|
|
