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Definition
| • is often used to indicate that more than two methods are used in a study with a view to double (or triple) checking results. |
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| draws inferences about the possible effect of a treatment on subjects, where the assignment of subjects into a treated group versus a control group is outside the control of the investigator |
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Mail questionnaire
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Definition
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• Inexpensive
• Reach a wide number of people
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• Low response rate
• Not good for detailed questions |
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• Personal interview
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Definition
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• Ability to probe and ask follow up questions
• Easier for respondent
• Better for opinions
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• Time consuming
• Resource intensive |
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• Telephone interview
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Definition
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• Allow for personal contact
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• Not everyone is listed
• Need to be short to avoid intrusion |
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Term
| o closed-ended questionnaire |
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Definition
• Respondents’ answers are limited to a fixed set of responses. Most scales are closed ended. Other types of closed ended questions include:
• Yes/no questions - The respondent answers with a “yes” or a “no”. |
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| • No options or predefined categories are suggested. The respondent supplies their own answer without being constrained by a fixed set of possible responses. Examples of types of open ended questions include: |
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| filter and contingency questions |
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Definition
filter questions used to establish a group
contingency only used if the person provides a fitting response to the filter question |
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• can the question be understood?
• What assumptions does the question make? |
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• Easy questions first
• Precede sensitive questions with an easier warm up
• start with easy, nonthreatening questions
put more difficult, threatening questions near end
never start a mail survey with an open-ended question
for historical demographics, follow chronological order
ask about one topic at a time
when switching topics, use a transition
reduce response set (the tendency of respondent to just keep checking the same response)
for filter or contingency questions, make a flowchart |
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Term
| Public Opinion poll evaluation |
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Definition
• What is the purpose of the poll?
• Who is the sponsor of the poll?
• Who is the organization that conducted the poll?
• What questions were asked?
• In what order were the questions asked?
• Who was polled?
• How were the interviews conducted?
• When was the poll done?
• What statistics are offered to substantiate accuracy? |
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Term
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Definition
ad
o Group discussion produces data and insights that would be less accessible without interaction found in a group setting—listening to others’ verbalized experiences stimulates memories, ideas, and experiences in participants.
o Group members discover a common language to describe similar experiences. This enables the capture of a form of “native language” or “vernacular speech” to understand the situation
o Focus groups also provide an opportunity for disclosure among similar others in a setting where participants are validated. For example, in the context of workplace bullying, targeted employees often find themselves in situations where they experience lack of voice and feelings of isolation.
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less control
irrelevant issues come up
not large enough to be representative
only one shot at data collection
observer dependancy |
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Term
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Definition
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o The advantages of field research are that people are closer to real world conditions
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o it takes time for the business to gather the information and that it is likely to be of a small sample size due to the high costs and time it takes. |
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Secondary research analyisis
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Definition
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o Cheaper and faster than original research
o May have access to larger sample size
o How much and which data you use is flexible
• Use part
• Subsidize your own research
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o May not be available
• Since many surveys deal with national populations, if you are interested in studying a well-defined minority subgroup you will have a difficult time finding relevant data.
o Secondary analysis can be used in irresponsible ways. If variables aren't exactly those you want, data can be manipulated and transformed in a way that might lessen the validity of the original research. |
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Definition
| • "the study of recorded human communications, such as books, websites, paintings and laws." |
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| measures of central tendency |
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| mode- mean and median cannot be determined |
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| mode or median, mean cannot be determined |
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| is variability or spread in a variable or a probability distribution |
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o Statistical dispersion can be measured in most of the usual ways, which just involved differences or averaging, such as range, interquartile range, and standard deviation.
No dividing so nothing that requires a ration |
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Term
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Definition
| o In addition to the measures of statistical dispersion defined for interval variables, such as range and standard deviation, for ratio variables one can also define measures that require a ratio, such as studentized range or coefficient of variation |
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Term
| (Z) distribution-properties |
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Definition
• is a continuous probability distribution that is often used as a first approximation to describe real-valued random variables that tend to cluster around a single mean value.
• No value at a point |
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Term
| Proportional reduction in error |
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Definition
• the relationship between the variables and the proportional reduction of error deals with the concept that one variable is capable of predicting the other.
• is a more restrictive framework widely used in statistics, in which the general loss function is replaced by a more direct measure of error such as the mean square error. |
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Term
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Definition
• A polynomial or function with exactly two variables
the analysis of two variables (often denoted as X, Y), for the purpose of determining the empirical relationship between them.[1] In order to see if the variables are related to one another, it is common to measure how those two variables simultaneously change together
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Term
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Definition
o is used in multivariate analysis of variance (MANOVA analysis) to compare group means on a combination of dependent variables.
• 0 to 1
• used with a nominal level of measurement
• make the fewest wrong guesses
• example |
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Definition
• 0 to + or -1
• used with an ordinal level of measurement
• measures association |
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Term
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Definition
• is a statistic used to measure the association between two measured quantities. A tau test is a non-parametric hypothesis test which uses the coefficient to test for statistical dependence.
• If the agreement between the two rankings is perfect (i.e., the two rankings are the same) the coefficient has value 1.
• If the disagreement between the two rankings is perfect (i.e., one ranking is the reverse of the other) the coefficient has value −1.
• If X and Y are independent, then we would expect the coefficient to be approximately zero.
• Measures association |
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Term
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Definition
• -1 to 1
-1 perfect negative correlation
1 perfect correlation
small effect size, r = 0.1 − 0.23; medium, r = 0.24 − 0.36; large, r = 0.37 or larger.
Measures linear relations |
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Term
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Definition
• 0 to 1
• =r^2
• In the case of paired data, this is a measure of the proportion of variance shared by the two variables
• Measures proportion of variance shared by the two variables |
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Term
| elaboration of the bivariate relationship |
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Definition
• Adding control variables to further understand the relationship
• Increases non spuriousness |
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Definition
| in which two events or variables have no direct causal connection, yet it may be wrongly inferred that they do, due to either coincidence or the presence of a certain third, unseen factor |
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Definition
• Controlled when we take into account its affect on the variables in the bivariate relationship
The control variable is something that is constant and unchanged in an experiment.
• Could explain the relationship between x and y
• Because x and y might not be truly linked but rather the product of some third variable (control) |
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| statistical hypothesis testing |
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Definition
| The theory, methods, and practice of testing a hypothesis by comparing it with the null hypothesis |
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Term
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Definition
| • A type of hypothesis used in statistics that proposes that no statistical significance exists in a set of given observations. The null hypothesis attempts to show that no variation exists between variables, or that a single variable is no different than zero. It is presumed to be true until statistical evidence nullifies it for an alternative hypothesis. |
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| is a proposed explanation for a phenomenon. |
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| is the distribution of a given statistic based on a random sample of size n. It |
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| • The set of values of the test statistic for which the null hypothesis is rejected. |
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Definition
| • also known as false positive, occurs when a statistical test rejects a true null hypothesis (H0). For example, a patient is healthy, null hypothesis states that he is healthy, but the test rejects the hypothesis, falsely suggesting that the patient is sick. |
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Term
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Definition
| • also known as false negative, occurs when the test fails to reject a false null hypothesis. For example, a patient is sick, null hypothesis states that he is healthy and the test fails to reject the hypothesis, falsely suggesting that the patient is healthy. |
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Definition
| • in which only one of the rejection regions "sufficiently small" or "sufficiently large" is preselected according to the alternative hypothesis being selected, and the hypothesis is rejected only if the test statistic satisfies that criterion. |
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Term
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Definition
| • is a statistical test used in inference, in which a given statistical hypothesis, H0 (the null hypothesis), will be rejected when the value of the test statistic is either sufficiently small or sufficiently large. |
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