Comm 398 Test 2

What is descriptive statistics?

Numbers that supply information about the sample or the variables

Types of experimental research : Classical Experiment

includes independent and dependent variables; has pre-testing and post-testing; has both experimental and control groups; conducts manipulation checks

Survey Population

cluster of elements you're drawing your sample from

Disadvantages of content analysis as a research method

limited to recorded materials issues of reliability and validity

Sampling Frame

list identifying the chosen sample

Sampling Error

degree to which a sample differs from the characteristics of the population

Weakness(s) of the Quasi or "Natural" Experiment

does not allow researchers to infer cause and effect

Probability Sampling Theory

each element in a given population stands for an equal chance of being selected into a sample

The Convenience Sample

easy to do, often for exploratory studies; no statistical meaning other than about that group

Advantages of content analysis as a research method

economical safe and easy to replicate

Standard Deviation

estimated average deviation of scores from the mean

How are the questionnaires constructed?

format : each question is distinguishable administering the questionnaire

What are the measures of dispersion in descriptive statistics

range variance standard deviation percentiles : the statistical ranking of a given score in a data set

Types of experimental research : the Quasi-Experiment or "Natural" Experiment

research design in which variation in the independent variable is natural, or not manipulated by the researcher; participants are not assigned randomly to treatment and control groups

What are the characteristics of quantitative research?

research that relies on numerical measurement; data is organized using graphs and charts; surveys

Judgement Sample

researcher decides what they think is the best group to sample; the characteristics of the chosen group are required for the study

What is a sampling frame?

the set of people or elements that are available to be selected as part of the sample

Sampling Bias

the systematic exclusion of population members due to the procedures of sampling

Population

the totality of any definable group of elements

Sampling Unit

the type of element to be selected in a sample a. Primary (WWU) b. Secondary (Comm class) c. Final sampling unit (Jr. and Sr. students)

Element

the unit of analysis (the characteristic under study)

What are the differences between descriptive and inferential statistics?

1. Descriptive: organize, analyze, and present data in a meaningful way Inferential: compares, tests, and predicts data 2. Descriptive: charts, graphs, and tables Inferential: probability 3. Descriptive: used to describe a situation Inferential: used to explain the chances or occurrence of an event 4. Descriptive: explains the data, which is already known, to summarize a sample Inferential: attempts to reach the conclusion to learn about the population, that extends beyond the data available

What is inferential statistics?

1. Statistical tests that provide information about the relationships between or among variables in the study 2. Help researchers test hypotheses and answer research questions+derive meaning from the results 3. Rely on several assumptions: the use of probability in establishing sig. levels, normal distribution of populations and samples, and random assignment of participants to groups

Types of random sampling

1. simple : each member of the population has the ability to be selected 2. stratified : the population is divided according to subgroups of interest, or homogenous groups 3. clustered : same as stratified but is in a different category 4. multistaged

How is descriptive statistics used by researchers?

Used to make value judgements or inferences about what the data means

What is random sampling?

a statistical basis, and the most rigorous way, for identifying whom or what to include as part of a sample

Sample

a subset of a population (a piece of the pie)

Weaknesses of the Classical Experiment

a. experimentation by the nature of its design characteristics will be inappropriate or impossible to use in all situations b. experimental forms cannot guarantee that some factor, other than the treatment factor, produced the significant effect c. participants may react to the artificiality of the lab experiment because of the manipulation of the independent variable d. lack of reality in experimental designs

Strengths of the Classical Experiment

a. researchers can manipulate the independent variable to observe changes in the dependent variable b. because of that ability to manipulate the variables, this allows testing of extremes and multiple replications c. can be more cost effective and convenient d. easy to replicate e. variables can be isolated

Strengths of the Quasi or "Natural" Experiment

a. the variation that communication scholars are often interested in exists naturally b. addresses the real world in a way that experimentation cannot (i.e. because of it being unethical)

What are the measures of central tendency in descriptive statistics?

mean median mode bimodal : a distribution that has two modes

What are the characteristics of experimental research?

most often conducted in a laboratory or in other simulated environments that are controlled by researchers; chosen when a research wants to determine causation

Variance

the average of squared differences of scores from the mean

Mean

the average; most common measurement of central tendency

Confidence Levels/Intervals

the estimated range calculated from a given set of sample data (range)

Median

the middle number between the smallest and largest number

Mode

the number that appears most often in a set

What are population and samples, and the relationship between them?

the population is the totality of any definable group of elements, whereas samples are a subset (or small piece) of that population