Methods of Research

Describe the characteristics of non-experitmental research.
1. non-random sampling – can be intact or volunteer
2. small ample sizes, less than 30
3. nominal or ordinal levels of measurement
4. population is not known to be normally distributed
types of study – survey, correlation, decriptive, or historical

answers “what is” or “what was”

Describe nominal, ordinal and interval level scales of measurement.
interval level scale measures in equal increments

nominal level scale counts or tabulates the number of occurences within a classification

ordinal level scale places variables in rank order

How do you select an inferential test of significance for an experimental and a correlation research study?
Determine whether a parametric or non-parametric test of significance is needed:

Parametric Assumptions
1. use tests of high validity and reliability
2. must have interval level of measurement
3. must be over 30 subjects
4. population is known to be normally distributed
5. scores of pre/post standardized tests must be normall distributed
6. set level of significance

Non-parametric assumptions
1. use tests of high validity and reliability
2. must have nominal or ordinal level measurement
3. samples are often non-random
4. sample sizes are small – less than 30
5. population are not known to be normally distributed
6. set level of significance

Once the test category is determined, select an appropriate statistical test.

Describe the words reliabilty and validity as they relate to research
reliability – how accurately and consistently a test measures from one administration to the next administration of the test on the same population. Reliable tests yield similar scores between administrations

validity – how well do the items on a test measure what they are supposed to measure

Describe a variable and its use in research.
a variable is a trait or object that must be able to change and be measurable.
Describe the difference between a research question and a hypothesis
research question – states the problem and gives the interaction between the variables

hypothesis – gives additional information such as testing materials, period of tiem and how the sample was selected

Describe the relationship between independent and dependent variables
independent variable is the treatment

dependent variable is the change brought about by the treatment

Describe the difference between internal and external validity
internal validity represents controls to secure the integrity or deal with the threats of the study. The seven threats are: time, loss of subjects, maturation, selection errors, testing, changes in measurement and statistical regression

external validity – the ability to generalize the results of the study back to the population it represnts

Describe the difference between a research hypothesis and a null hypothesis
research hypothesis states that there will be a statistically significant difference or relationship between variables

null hypothesis states that there will be no significant difference or relationship between variables. If there is a significant difference, the null hypothesis is rejected.

Describe an experimental group and a control group
experimental group receives a particular treatment. Dependent variable that is expected to change.

control group- independent variable – receives no treatment or a different treatment and should not be contaminated

Describe the characteristics of experimental research
use parametric assumptions
1. random sampling
2. larger population – sample of 30 or more
3. uses an experimental and control group
4. interval measurements
5. population is known to be normally distributed
Describe the difference between quantitative and qualitative research
quantitative – exact mathematical value so difference between 2 or more variables is statistically analyzed for significance

qualitative – classifying by using word descriptions to determeine value, rank or position of a variable under study

Describe the difference between a popluation and a sample
a population is a whole group with its own characteristics and varies in size

a sample is a representative portion of a defined population

Describe the difference between random sampling and intact group
intact group – entire population, can be volunteer

random sampling – a group that is chosen randomly to represent the popluation. Each individual in the population has an equal chance of being selected

Describe the word siginificant as it relates to research
Decide if there is a significant difference between the experimental group and the control group using an inferential test of significance at a pre-determined level. In education, an alpha level of significance (.05) is often used.
Describe the difference between a research article and an opinion article
Opinion articles are subjective – they express the beliefs, speculations or evaluations or the author of other sources consulted

research is objective and does not show biases of the person doing the research

Decribe the difference between descriptive statistics and inferential statistics
descriptive statistics uses percentages, averages, frequency distributions and measures of central tendency to describe and identify the characteristics of variables of groups under study

inferential statistics primarily deals with the question: is the difference or relationship between vairables great enough to rule out chance factors as having produced a difference or relationship