Stats exam 1

collection of all units of interest (people, households, geographic regions, time periods)

a subset of a population that is actually observed.

the characteristics of the population

a descriptive measure associated with a random variable of a population

descriptive measure associated with a random variable of a sample

any characteristic that is recorded for subjects in a study

observations on it take numerical values that represent different magnitudes of the variables

if each observation belongs to one of a set of categories

continuous and discrete

if its possible values form a set of separate numbers, such as 0, 1, 2, 3, ..

if its possible values form an interval

nominal, ordinal, interval, and ratio

qualitative only, categorized using names, labels, or qualities. No ranking, or order

qualitative or quantitative, can be arranged in order, but differences b/w data entries are not meaningful, ranks

quantitative, can be ordered, distances and you can calculate meaningful differences betweendataentries

similar to data at the interval level, with the added property that a zero entry is an inherent zero.

Random and Systematic errors

random and inherently unpredictable events in the measurement process

when there is a problem in the measurement system

describes how closely a measurement matches an actual value

describes the amount of detail in a measurement.

outcome variable on which comparisons are made(output)

defines the groups to be compared with respect to values on the response variable(input)

esearcher observes values of the response variable and explanatory variables for the sampled subjects, w/o anything being done to the su

observation study that provides information about a population at a particular point in time

study that observes a population in the present using a sample survey and proceeds to follow the subjects in the sample forward in time in o

study that observes a population in the present using a sample survey and also collects information about the subjects in the sample regardi

assigns to each subject a treatment (an experimental condition) and then observes theoutcome on the response variable

the list of subjects in the population from which the sample is taken.

simple random sample, stratified random sample, cluster random sample, systematic sample, convenience sample

of n subjects from a population is one in which each possible sample of that size has the same chance of being selected (good, but expensive

divides the population into separate groups, called strata, and then selects a simple random sample from each stratum

divides the population into a large number of clusters, selects a simple random sample of the clusters, and then choose all members in them

selects some starting point and then selects every kth member of the population

Personal interviews, telephone interview, self-administered questionnaire, direct observation

Sampling bias,Nonresponse bias,Response bias

amples that are easy to obtain.In a volunteer sample, the subjects volunteer to participate. (the participants may have opinions that are no

ccurs when the subject gives an incorrect response, or the question wording or the way the interviewer asks the questions is confusing or mi

occurs when some sampled subjects cannot be reached or refuse to participate or fail to answer some questions.

occurs from using nonrandom samples or having a sampling frame that lacks representation from parts of the population.

the physical entity to which the treatment is randomly assigned or the subject that is randomly selected from one of the treatment populatio

the physical entity on which a measurement is taken.