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