Measurements, estimation and data analysis

Question 1

give me 5 points of Strategic( Organisational Level) Long term

Answer 1

-reducing costs
– expanding customer base
– increasing user satisfaction
– improving productivity
– reducing time-to-market

Question 2

Give me 2 points of Tactical (Project Level) Medium term

Answer 2

Quality, Time, Cost, Productivity
– Process varies from project to project - compare:
* RAD* of low-cost single-user desktop tool
* enterprise-wide IS project

Question 3

what is Operational: activity level (short term)

Answer 3

Day-to-day, week-to-week activities which vary greatly depending on the project’s process

Question 4

what is the purpose of measurement estimation and data analysis

Answer 4

To support reliable Quantitative comparisons evaluations, predictions and decision making relevant to software projects and their artifacts

Question 5

What is a measurement

Answer 5

Measurement is the process of assigning a value to some attribute of entity, where the value is obtained on a particular scale.

Question 6

What is a measurement instrument

Answer 6

Something we use to measure

Question 7

What to measure? Product

Answer 7

Product
– Specifications, designs, test plans, modules, programs…

Question 8

What to measure? Process

Answer 8

• Process
  – Change control, design, project scheduling, review…

Question 9

What to measure? Resource

Answer 9

Personnel, Money, hardware and Software

Question 10

Attributes that are difficult to measure

Answer 10

Complexity, Productivity and Quality, length of time before program stops, the halting program

Question 11

What is a Unit?

Answer 11

A measurement is a scalar Quantity, defined and adopted by convention, with which any other quantity of the same kind can be compared to express the ratio of the two quantities as a number.

Question 12

how can software size be measured?

Answer 12

Characters,Bytes,Modules, classes and SLOC(Source Lines of Code)

Question 13

What is Direct Measurement

Answer 13

An attribute that can be measured without the need to measure another attribute. e.g.
Length of source code
Duration of testing process
Number of defects discovered

Question 14

What is Indirect Measurement

Answer 14

something you cant directly measure but can calculate from other measurements.
Length of a project, Length of development+length of testing
Developer-Days (Num of developrs* num of days)
Programmer productivity(SLOC/Timespent)

Question 15

What makes a measurement valid?

Answer 15

– accurate – measures the true value of the attribute

– reliable – repeated measurements give similar values

– meaningful – the measurement answers a question that we want answered
Measurement validity

Question 16

What makes a measurement accurate

Answer 16

Accuracy is important, but needs to be tempered by context

• Acceptability of accuracy varies
  – If we’re measuring file size, we expect 100% accuracy
  – If we’re measuring number of defects, perhaps ± 10%
• Timeliness is more important
  – An approximate number of defects tells us whether the software is ready to ship
  – A precise number of defects doesn’t add value, but may take time to determine (and can never
  be guaranteed as accurate)
  Measurement accuracy

Question 17

Why do we put data onto a scale?

Answer 17

We need to put data onto a scale to see how it compares to anoher piece of Data

Question 18

What are the 5 types of scales

Answer 18

-Nominal
– Ordinal
– Interval
– Ratio
– Absolute
* Data on a different scale conveys a different level of precision
Scale types

Question 19

Define Nominal

Answer 19

All we can do with the data is categories it
All we can say s if they are in the same category or not

Question 20

Define Ordinal

Answer 20

you can categorise them and rank them, but we dont have any indication of the gap between them

Question 21

Define Interval

Answer 21

We can categorise and rank and has equal intervals, but there is no Zero point, so we cannot make claims that x is twice and big than y

Question 22

Define Ratio

Answer 22

Can categorise, rank and has equal intervals, but there can be a 0 point
you can say twice as big

Question 23

Define Absolute, subset of ratio

Answer 23

Cannot determine indirectly frm other measurement, used for counting things. e.g. Number of defects detected by a certain test method, number of lines of code, reused from a previous project, cannot be changed in any way.

Question 24

Admissible transformations

Answer 24

Can we take data from a scale and transform it, to the same data on another scale

Question 25

What is Spoilage? and what scale type is it?

Answer 25

SP =
Time to fix post-release defects/
Total development time

Ratio a value of Zero would mean no time fixing post release defects.

Question 26

What might an atypically large value for SP mean?

Answer 26

Unusually large amount of time on fixing defects, unusually small
amount of time on development, or both

Question 27

What is estimation:

Answer 27

Estimation is the process of predicting a expected value for some attribute, (whos value is not known)

Question 28

What is top down?

Answer 28

estimate an overall value and then proportionately distribute this over the components

Question 29

When is Top down appropriate?

Answer 29

When the project completion time is fixed

Question 30

What is bottom up?

Answer 30

Estimate a value for individual component and then obtain the overall figure.

Question 31

When is bottom up appropriate?

Answer 31

For an open ended research project