lecture # 03 measurement scales

Measurement ScalesDr. Akhlas Ahmed

Greenwich UniversityLecture # 03 July 11th 2014

Makeup Class

Measurement:

To collect data, you need to have something to measure

Measurement is the process of assigning numbers or scores to characteristics or attributes of the objects.

Variables:• When we measure the attributes of an object,

we obtain a value that varies between objects.

• For example consider the people in this class as objects and their height as the attribute

• The attribute height varies between objects, hence attributes are more collectively known as variables

• Variables can be measured on four different scales

Nominal

Ordinal?

Interval

Ratio

Types of Scales

• Nominal - Identification only– Example (players numbers, male=1 female=0)

• Ordinal -Ranking– Example (grades?) SEI score

• Interval –Ranks and distinguishes intervals– Example (temperature)

• Ratio – absolute quantities– Example (weight, degrees Kelvin)

• Nominal Scale – Categorizing • Numbers (Political Party)

• Ordinal – Order – Ranking (Magnitude)• You can order objects in terms of having more or less of some quality• Order (Rank Order of Finish in a Race)

• Interval - Distance (Equal Intervals)• The distance between adjacent points on the scale is identical• Equal Intervals (Temperature)

• Ratio - Origin (Absolute Zero Point)• Zero “means something” (absence of a given quality)• Order, Equal Intervals, Absolute Zero (Number of Cars)

o Classifies data according to a category only.

o E.g., which color people select.

o Colors differ qualitatively not quantitatively.

o A number could be assigned to each color, but it would not have any value.

o The number serves only to identify the color.

o No assumptions are made that any color has

more or less value than any other color.

Nominal Scale

Which of the following media influences your purchasing decisions the most?

–1 Television

–2 Radio

–3 Newspapers

–4 Magazines

Nominal Scale

Ordinal Scaleo Classifies nominal data according to some order or rank E.g. names ordered alphabetically

o With ordinal data, it is fair to say that one response is greater or less than another.

o E.g. if people were asked to rate the hotness of 3 chili peppers, a scale of "hot", "hotter" and "hottest" could be used. Values of "1" for "hot", "2" for "hotter" and "3" for "hottest" could be assigned. The gap between the items is

unspecified.

Ordinal Scale

Please rank the news programs offered in following four networks based on your preference.(1 for most preferred, 4 for least preferred).

_____ CTV

_____ Global

_____ A Channel

_____ CBC

Interval Scale

o Assumes that the measurements are made in equal units.

o i.e. gaps between whole numbers on the scale are equal.

o e.g. Fahrenheit and Celsius temperature scales

o An interval scale does not have to have a true zero. e.g. A temperature of "zero" does not mean that there is no temperature...it is just an arbitrary zero point.

o Permissible statistics: count/frequencies, mode, median, mean, standard deviation

Interval Scale

How likely are you going to buy a new automobile within the next six months? (Please check the most appropriate category)

Definitely will not buy ___ 1

Probably will not buy ___ 2

May or may not buy ___ 3

Probably will buy ___ 4

Definitely will buy ___ 5

Ratio Scaleo Similar to interval scales except that the ratio scale has a true zero value.

o e.g. the time something takes

o Allows you to compare differences between numbers.

o Permits full arithmetic operation.

o If a train journey takes 2 hr and 35 min, then this is half as long as a journey which takes 5 hr and 10 min.

7 38

ScaleNominal Numbers

Assigned to Runners

Ordinal Rank Orderof Winners

Interval PerformanceRating on a

0 to 10 Scale

Ratio Time to Finishin Seconds

Thirdplace

Secondplace

Firstplace

Finish

Finish

8.2 9.1 9.6

15.2 14.1 13.4

Primary Scales of Measurement

Scale Basic Characteristics

Common Examples

Marketing Examples

Nominal Numbers identify & classify objects

Social Security nos., numbering of football players

Brand nos., store types

Ordinal Nos. indicate the relative positions of objects but not the magnitude of differences between them

Quality rankings, rankings of teams in a tournament

Preference rankings, market position, social class

Ratio Zero point is fixed, ratios of scale values can be compared

Length, weight Age, sales, income, costs

Interval Differences between objects

Temperature (Fahrenheit)

Attitudes, opinions, index

Primary Scales of Measurement

A Classification of Scaling Techniques

Figure 8.2

Likert Semantic Differential

Stapel

Scaling Techniques

NoncomparativeScales

Comparative Scales

Paired Comparison

Rank Order

Constant Sum

Q-Sort and Other Procedures

Continuous Rating Scales

Itemized Rating Scales

Likert ScaleThe Likert scale requires the respondents to indicate a degree of agreement ordisagreement with each of a series of statements about the stimulus objects.

Strongly Disagree Neither Agree Strongly disagree agree nor agree

disagree 1. Sears sells high-quality merchandise. 1 2X 3 4 5 2. Sears has poor in-store service. 1 2X 3 4 5 3. I like to shop at Sears. 1 2 3X 4 5

• The analysis can be conducted on an item-by-item basis (profile analysis), or a total (summated) score can be calculated.

• When arriving at a total score, the categories assigned to the negative statements by the respondents should be scored by reversing the scale.

Stapel ScaleThe Stapel scale is a unipolar rating scale with ten categoriesnumbered from -5 to +5, without a neutral point (zero). This scale is usually

presented vertically.

SEARS

+5 +5+4 +4+3 +3+2 +2X+1 +1

HIGH QUALITY POOR SERVICE-1 -1-2 -2-3 -3-4X -4-5 -5

The data obtained by using a Stapel scale can be analyzed in thesame way as semantic differential data.

Semantic Differential ScaleThe semantic differential is a seven-point rating scale with end points

associated with bipolar labels that have semantic meaning.

SEARS IS:

Powerful --:--:--:--:-X-:--:--: Weak

Unreliable --:--:--:--:--:-X-:--: Reliable

Modern --:--:--:--:--:--:-X-: Old-fashioned

• The negative adjective or phrase sometimes appears at the left side of the scale and sometimes at the right.

• This controls the tendency of some respondents, particularly those with very positive or very negative attitudes, to mark the right- or left-hand sides without reading the labels.

• Individual items on a semantic differential scale may be scored on either a -3 to +3 or a 1 to 7 scale.

-3 -1 0 +1 +2-2 +3

Cheer

Cheer detergent is:Cheer detergent is:

1) Very harsh --- --- --- --- --- --- --- Very gentle

2) Very harsh 1 2 3 4 5 6 7 Very gentle

3) . Very harsh . .

. Neither harsh nor gentle . . . Very gentle

4) ____ ____ ____ ____ ____ ____ ____ Very Harsh Somewhat Neither harsh Somewhat Gentle Very harsh harsh nor gentle gentle gentle

5) Very Neither harsh Very

harsh nor gentle gentle

Rating Scale Configurations

Balanced and Unbalanced Scales

Jovan Musk for Men is: Jovan Musk for Men is: Extremely good Extremely good Very good Very good Good Good Bad Somewhat goodVery bad Bad Extremely bad Very bad

Thanks