assigning the characteristics of objects to a number or a symbol.
the unique labels or descriptors that are used to designate each value of the scale. All scales possess description.
the relative sizes or positions of the descriptors. Numbers indicate the relative extent to which the objects possess some characteristic. Order is denoted by descriptors such as greater than, less than, and equal to.
: the absolute differences between the scale descriptors are known and may be expressed in units. Equal distances on the scale equal values in the characteristic measured. Distance implies order, but reveres might not be true.
that the scale has a unique or fixed beginning or true zero point. (the "0" point has a unique, real meaning, that cannot be substituted with other numbers)
Ex: 1 male 2 female
example of nominal scale
description and order
Ex: rating soccer teams based upon their points scored
example of ordinal scale
description, order, and distance
Ex: ranking soccer teams in order with equal distance in between each
example of interval scale
Ex: strongly disagree, agree, neither, disagree, and strongly disagree
example of interval scale
description, order, distance, and origin
Ex: what is your annual income? ____
example of ratio scale
describes how the measurement is obtained
Comparative scale technique
: involve the direct comparison of stimulus objects. ? data must be interpreted in relative terms
: A respondent is presented with two objects and asked to select one according to some criterion.
Rank Order Scaling
: Respondents are presented with several objects simultaneously and asked to order or rank them according to some criterion.
Constant Sum Scaling
Respondents allocate a constant sum of units, such as 100 points to attributes of a product to reflect their importance (e.g., preference, attitudes,..).
Advantages of Comparative Scales:
Small differences between stimulus objects can be detected. • Same known reference points for all respondents. • Easily understood and can be applied.
Disadvantages of Comparative Scales:
Ordinal nature of the data (rank ordering and paired comparison) - You don't know how much more a product is preferred to another • Inability to generalize beyond the stimulus objects scaled.
Constant Rating Scale
Respondents rate the objects by placing a mark at the appropriate position on a line that runs from one extreme of the criterion variable to the other. The form of the continuous scale may vary considerably.
constant rating scale
what type of scale is this? Example Probably the worst ----------------*-----------------Probably the best
Itemized Rating Scales
: The respondents are provided with a scale that has a number or brief description associated with each category.
The Likert scale
requires the respondents to indicate a degree of agreement or disagreement with each of a series of statements about the stimulus objects
The semantic differential
: is a rating scale with end points associated with bipolar labels that have (opposite) semantic meaning.
What type of scale is this? EX: Powerful - - - - - - -Weak
Rules for Individual question content
is the question necessary? Are several questions needed instead of one? Can the respondent remember? effort required avoid ambiguous questions avoid generalizations and estimates order of questions
used to describe the data set
Measures of central tendency
used to report a single piece of information that describes the most typical response to a question
the average value characterizing a set of numbers
: the value in a string of numbers that occurs most often
the value whose occurrence lies in the middle of a set of ordered values
Measures of variability
: used to reveal the typical difference between the values in a set of values
reveals the number (percent) of occurrences of each number or set of numbers
identifies the maximum and minimum values in a set of numbers
• Standard deviation
indicates the degree of variation in a way that can be translated into a bell-shaped curve distribution
sum of the count/ percentage all of the preceding numbers plus the present one
is the mean squared deviation from the mean. The variance can never be negative
The standard deviation
is the square root of the variance. (Tells you how far apart from the mean are, on average, the observations in your dataset)
: used to generate conclusions about the population's characteristics based on the sample data
: used to compare means
. Associative analysis
determines the strength and direction of relationships between two or more variables
. Predictive analysis
allows one to make forecasts for future events
The target ? is the collection of elements or objects that possess the information sought by the researcher and about which inferences are to be made.
on the other hand, is a subgroup of the population selected for participation in the study
A ? is a summary description of a fixed characteristic or measure of the target population. A ? denotes the true value which would be obtained if a census rather than a sample was undertaken.
A ? is a summary description of a characteristic or measure of the sample. The sample ?is used as an estimate of the population parameter.
A Confidence interval
tells that there "X"% of the samples means drawn from that population will have a mean within in a certain interval (sample mean ± T)
Confidence Interval equation
= x (+or -) T
This is what we got from the sample (i.e., $18)
Tolerance (your book call this sample error) z* s/square root of n
when is t test appropriate?
when the sample size is less than or equal to 30
when is the p test appropriate?
when the sample size is greater than 30
Duncan Post Hoc Test
when the group means are not equal which test do you use to find out which group is different?