Group 25 presents on the interval level of measurement. Members contributed by collecting data, designing slides, and examples. Interval level is quantitative with meaningful differences between values but no natural zero. Stanley Stevens introduced the four levels of measurement including interval. Interval data has equal-sized units and statistics like mean and standard deviation can be calculated. Examples shown are temperature, generations, and GPA. A survey of IIUM students' GPA over two semesters is presented with results.

1. GROUP 25 OF ECON 1140 SECTION 01 AND 02 PRESENTS
INTERVAL LEVEL OF
MEASUREMENT

2. MEMBERS & CONTRIBUTIONS
AMIRAH FARHANIS BINTI
MUHAMMAD DZULKIFLI
-1624964- SECTION 2
● Data Collections - General
Information about this topic
● Design overall slides
● Compile materials
YOUSRA ABRABAR
-1629748- SECTION 2
● Year interval example
● Conclusion
OMAR SALEEM MOHAMMED
-1627957- SECTION 2
● Preparation of survey
questions
● Data collections
AIN ATIYA AZMI BINTI NAZMI
-1710222- SECTION 1
● Conducting survey
● Presentation,
computation and data
analysis
● Compile materials
MUHAMMAD ASHRAF MOHD SAM
-1612709- SECTION 2
● Interval data VS other datas
EL MOUSTAPHA SIDIMOUHAMED
-1622567- SECTION 1
● GPA example
● Conclusion

3. WHAT IS INTERVAL LEVEL?
● The third of interval level of measurement is characterized
by a scale that is quantitative in nature.
● Similar to the ordinal level, with the additional property
that meaningful amounts of differences between data
values can be determined.
● There is no natural zero point.

4. Stanley Smith Stevens
● Stanley Smith Stevens (November 4, 1906- January
18, 1973) was an American psychologist who founded
Harvard’s Psycho-Acoustic Laboratory studying
psychoacoustics.
● In 1946, he introduced a theory of level
measurements widely used by scientists but criticized
by statisticians.
● Psychologist Stanley Smith Stevens developed the
best known classification with four levels or scales of
measurement such as nominal, ordinal, interval and
ratio.
Source : Wikipedia

5. INTERVAL DATA vs OTHER DATAS
Attribute Interval Nominal Ordinal Ratio
Other Name
Unit size fixed or
Equal Interval
Set or Categorical
Fully ordered,
rank ordered
Zero or ref.pt
fixed
Statistics
ANOVA, mean,
Standard
Deviation
Count, Mode, chi-
squared
median, rank
order correlation
logs
Example centigrade scale
Set of
participants,
makes of car
order of finishing
a race
Degrees Kelvin or
absolute
Types of
absolute
intervals,
differences
Identity of
individual entities
order, sequence ratios, proportions

6. To Compute Interval Nominal Ordinal Ratio
Frequency
Distribution
Yes Yes Yes Yes
Median And
Percentiles
Yes No Yes Yes
Add Or Subtract Yes No No Yes
Mean, Standard
Deviation,
Standard Error Of
The Mean
Yes No No Yes
Ratio, Or
Coefficient Of
Variation
No No No Yes

7. Example 1:
Temperature
When we measure temperature (in
Fahrenheit), the distance from 20-30 is
same as distance from 90-100.
The interval between values is
interpretable.

8. Example 2: Year Interval between
Generations Post-World War 2
Each generation covers equal 20-year age span
Baby Boomers
(1945 - 1964)
Generation X
(1965 - 1984)
Generation Y
(1985 - 2004)

9. Example 3: GPA Score
GPA represents a student’s average
performance in his studies over a period of time,
eg: one semester.
A score of 2.30 - 2.40 has the same distance as
a score between 3.70 - 3.80.

10. Survey on IIUM students GPA
for the past two semesters
Method Of
Data
Collection:
The data was collected by
using Google Forms
shared on IIUM students’
Whatsapp.
A total of 62 respondents
have taken part in this
survey.

14. Semester 1 GPA
The mode for
this data is
3.50-4.00.
A total of 24
out of 62
students
(38.74%)
scored dean
list in
semester 1.

15. Class
Interval
Lower
Limit
Upper
Limit
Midpoint
(x)
Frequency
(f)
fx (x-x̅) ²
2.00 - 2.50 1.95 2.45 2.25 2 4.5 1
2.50 - 3.00 2.45 2.95 2.75 20 55.0 0.25
3.00 - 3.50 2.95 3.45 3.25 16 52.0 0
3.50 - 4.00 3.45 3.95 3.75 24 90.0 0.25
Total 62 201.5 1.5

16. Mean:
Standard
Deviation:

17. Semester 2 GPA
The mode for
this data is
3.50-4.00.
A total of 26
out of 62
students
(41.94%)
scored dean
list in
Semester 2.

18. Class
Interval
Lower
Limit
Upper
Limit
Midpoint
(x)
Frequency
(f)
fx (x-x̅) ²
2.00 - 2.50 1.95 2.45 2.25 1 2.25 1.1449
2.50 - 3.00 2.45 2.95 2.75 15 41.25 0.2209
3.00 - 3.50 2.95 3.45 3.25 20 65.00 0.0049
3.50 - 4.00 3.45 3.95 3.75 26 97.50 0.1849
Total 62 206 1.5556

19. Mean:
Standard
Deviation:

20. CONCLUSION
● Measurement is a fundamental part of Statistics and every
research is as good as its measurement.
● The 4 levels of measurement ( nominal, ordinal, interval, ratio)
are created to determine how data should be summarized and
presented.
● Interval-level data is used for any quantitative variable, but it
should include equal space between each option of the scale.