You are a research scientist for the U.S. Department of Agriculture

You are a research scientist for the U.S. Department of Agriculture that has been asked to research the impact of permaculture and conventional farming methods on soil erosion. You identify 4 conventional farms, 4 permaculture farms, and 4 undisturbed natural areas. All of the farms and natural areas have streams that run nearby. Every week you measure the turbidity and sediment depth in the streams and compare the results after 2 years of data collection

a. Identify the independent variable(s) from the study above

b. Identify the dependant variable(s) from the study above.

c. List 2 variables that should be controlled in this study.

d. Why do you suppose 4 undisturbed natural areas were included in the study?

Solution: 8 A- the indipendant variables in the study are the numbers of different type of farms i.e. 4 conventional farms, 4 permaculture farms and 4 undisturbed areas.

Ans-B- the dependent variables include the turbidity and sediment depth of stream.

Ans-C- the two variables which should be controlled are turbidity and sediment depth of the stream.

Ans-D- four undisturbed natural area are included in this study to act as control sample.

Basic Econometrics Chapter 7, Problem 21

Question: Consider the following demand function for money in the United States for the period 1980-1998:

where M = real money demand, using the M2 definition of money

Y = real GDP

r = interest rate

To estimate the above demand for money function, you are given the data in Table 7.10.

Note: To convert nominal quantities into real quantities, divide M and GDP by CPI. There is no need to divide the interest rate variable by CPI. Also, note that we have given two interest rates, a short-term rate as measured by the 3-month treasury bill rate and the long-term rate as measured by the yield on the 30-year treasury bond, as prior empirical studies have used both types of interest rates.

TABLE 7.10

Demand for Money in the United States, 1980-1998

Source: Economic Report of the President, 2000, Tables B-1, B-58, B-67, B-71.


Notes: GDP: gross domestic product ($ billions).

    M2: M2 money supply.

CPI: Consumer Price Index (1982­-1984 = 100).

LTRATE: long-term interest rate (30-year Treasury bond).

TBRATE: three-month Treasury bill rate (% per annum).

a. Given the data, estimate the above demand function. What are the income and interest rate elasticities of demand for money?

b. Instead of estimating the above demand function, suppose you were to fit the function

 How would you interpret the results? Show the necessary calculations.

c. How will you decide which is a better specification? (Note: A formal statistical test will be given in Chapter 8.)


Given information:

The demand function for money can be written as follows:

…… (1)


Table -1 shows the data of Country U’s demand for money (1980 – 1998) as follows:


Table -2 shows the estimated result for short-term bond as follows:

From Table -2, the regression equation for short term can be written as follows:

…… (2)

Table -3 shows the estimated result for long-term bond as follows:

The regression result for 30-year long–term bond can be written as follows:

…… (3)

From Equations (2) and (3), the value of income elasticity is (0.5243 or 0.4946) and the interest rate elasticities are (-0.0255 or -0.0516). Here, the short-term interest rate (TBrate) gives a better statistical significant in this model.


The demand function is as follows:

…… (4)

Here, the ratio

represents the cost of holding money. It does not yield more interest income.

Table -4 shows the estimated result for the long term as follows:

The log regression result can be written as follows:

…… (5)

Table -5 shows the estimated result for a long-term bond as follows:

…… (6)

Both Equations (5) and (6) are bi–variate regression as per expectation K which is statistically significant to the interest rate. The results are more sensitive in the long-term interest rate than the short-term interest rate. Thus, the value of

in the long-term interest rate gives a better value than the short-term rate.


The formula for F-test is represented as follows:

…… (7)


RSS R is the residual sum of squares of the restricted regression.

RSS UR is the residual sum of squares of the unrestricted regression.

q is the number of linear restrictions.

n is the number of observations.

k is the number of parameters in the restricted regression.

The value of the F-test can be calculated using Equation (6) as follows:

Hence, the F-statistic is 10.6920.

In this case, it is observed that the result is based on the long-term rate that is similar. Models (2) and (3) are unrestricted and models (4) and (5) are restricted. Here, the dependent variables in the two models are not the same and there is only one restriction variable, which implies that the coefficient of variable Y in Model (1) is unity.

The critical F-value is 4.49 at 5% significance level. Therefore, based on the F-statistic, the model can be rejected, as it defines that the real income elasticity is smaller than unity.

XYZ, a software house is considering developing a payroll application for use in academic institutions

Question: XYZ, a software house is considering developing a payroll application for use in academic institutions and is currently engaged in a cost-benefit analysis. Study of the market has shown that, if XYZ can target it efficiently and no competing products become available, it will obtain a high level of sales generating an annual income of $800,000. It estimates that there is a 1 in 10 chance of happening. However, a competitor might launch a competing application before its own launch dates and then sales might generate only $100,000 per year. It estimates that there is a 30% chance of this happening. The most likely outcome it believes, is somewhere between these two extremes – it will gain a market lead by launching before any competitor product becomes available and achieve an annual income of $650,000. Initially, draw a table presenting the expected value ($) for high, medium and low sales. Show the total expected income. Development costs are estimated at $750,000. Sales levels are expected to be constant for at least four years. Annual costs of marketing and product maintenance are estimated at $200,000, irrespective of market share. Would you advise going ahead with the project? Give detailed explanation.


Income,Expected Value

High Sale, 1/10 * 800,000 = $80,000

Sale Low, 3/10*100,000 = $30,000

Medium Sale, 6/10*650,000 = $390,000

Expected Sales Level = 1/10*800,000 + 3/10*100,000 + 6/10*650,000

= $80,000 +  $30,000 + $390,000

= $500,000

Development Cost = $750,000

Annual Cost = $200,000

Total Cost over four years

= development cost + 4* Annual Cost

= $750,000 + $800,000

= $1,550,000

Total revenue over 4 years = $2,000,000

Profit = $450,000

Yes it is advisable to go ahead with the project as the firm is operating in profit.

A new project has an average novelty for the software supplier that is going to execute it.

Question: A new project has an average novelty for the software supplier that is going to execute it. Development flexibility is high, and requirements may change radically. The development team is all located at the same office and the software house as a whole tends to be formal in its standards and procedures. The product should be very reliable, and the algorithms are complex. The supplier would like to reuse the project with suitable modifications on further contracts. Developers are familiar with the platform and they are capable of conducting this specific type of project. The toolsets available to the development team are judged to be typical for this size of company, as is the degree of schedule pressure to meet a deadline. a. What would be the scale factor in this case? b. What would be the estimate of effort if the size of the application was estimated as in the region of 2000 lines of code? c. What would be the impact of all the effort multipliers on the project estimation?


The success of a software project depends on the stakeholder. A stakeholder outside the project organization can see success in terms of the final cost and time incurred while the internal stakeholders can find success in meeting the scope of the project. So we can say that project success criteria varies with the different groups of stakeholders.

A project is defined successful when it passes the quality checks meeting all the quality requirements,cost,time-lines and the agreed scope.
But if a project meets all these does not guarantees to be a successful one,there are projects that do not meet these requirements but are still successful.

successful projects are completed within time,budget,scope,performance requirements and user acceptance testing(UAT).

The main reason of a project failure is poor project management. Most of the factors like limited use of automation testing, automated planning ,improper utilization of resources, etc are associated with project failure are directly or indirectly related to project management.

In todays era, software firms has major problem of project failures due to schedule and cost overruns. To avoid this the software industries should be sensitized with using proper quality checks and automation using tools for estimation and project planning. Also project decisions should be taken after reviewing previous project experiences which should be recorded for future use.

Most of the industries use Know Error dB to save effort and time in resolving the same type of issues.
A software industry has different types of projects ,different relationship with the customers and different culture. Accordingly the project metrics should be defined to achieve success.

The perception of success depends on the role of the stakeholder(developer,manager,client,etc)

However below are the ten most important factors deciding projects success:-

1. Continuous Client feedback to developers
2. Skilled resources
3. Requirement reviewed and accepted by the development team
4. Continuous review and feedback from the project manager
5. Realistic project milestones
6. Structured and defined methodology
7. Project team involved in project decisions
8. Clear requirements
9. Clients support in case of requirement ambiguity
10. Good relationship and understanding b/w client and the project team

If you were asked as an expert to provide an estimate of the effort needed

Question: If you were asked as an expert to provide an estimate of the effort needed to make certain changes to an existing piece of software, what information would you like to have to hand to assist you in making that estimate?

Our teacher told us to get help from the internet but not to copy and paste. Our teacher told us to answer the questions briefly. This question very important for me. Please help me.

Lesson : Software Project Management. (Book: Software Project Management Bob Hughes and Mike Cotterell 5th edition)

Solution: Effort estimation for changes in a software project can be calculated using lines of code. But, before we estimate efforts, we need to estimate the size of the changes in terms of lines of code.

1. Using Function Points (Programming language independent)

We can count the number of functionalities that will be changed and then multiply that with the number of lines that will be needed to implement in a particular programming language (53 for Java)

2. Using Lines of Code directly (Programming language dependent)

Once we have the lines of code required for the changes, we can use one of the COCOMO models to estimate the efforts based on the number of lines of code.

There are 3 types of cocomo models for 3 types of different systems (based on size) and they have fixed values for the formula

Based on size of project

1. Organic

2. Semi-detached

3. Embedded

Based on degree of correctness or accuracy of estimation

1. Basic

2. Intermediate

3. Detailed (Break the software into modules and apply basic or intermediate cocomo)

Formula for Basic Cocomo

Software Projectsab

Effort (E) = a * (LOC)b

Formula for Intermediate Cocomo

Software Projectsab

Effort (E) = (a * (LOC)b )* EAF

Note: EAF stands for Effort adjustment factor and its value might usually be given in the question.

What criteria would you consider while choosing the right development/management approach to a particular project?

Question: What criteria would you consider while choosing the right development/management approach to a particular project? What are the differences between “heavyweight” and “lightweight” methodologies? Explain in details and provide examples. Describe briefly the agile methods.


To develop a particular project you have to consider the right approach which depends on several criteria discussed below.

1. The overall budget of that project

2. Manpower (Team size) needed to complete the project.

3. Decide which technology should use in that project.

4. Need any kind of training to the team member who is involved in that project.

5. Need a proper understanding of the criticality of the project.

6. Making proper documentation must be easy and simple.

7. Which tool and technique can be used?

8. The testing part is more important for the verification and validation of the project.

9. Maintenance of the project after delivery used software etc.

These are the major key point we have to consider to develop a project.

There is a huge difference between heavyweight and lightweight software

  1. Heavyweight methodologies need a high budget, for lightweight methodologies low budget needs.
  2. Heavyweight methodologies are very critical for lightweight methodologies is less critical as compared to Heavyweight methodologies.
  3. Heavyweight methodologies need large team size, they always maintain a certain hierarchy among team members. Lightweight methodologies need small size creative team generally 7 to 10 people.
  4. Heavyweight methodologies are process-oriented, in the case of, lightweight methodologies, it is people-oriented.
  5. Generally, it needs heavy training for heavyweight methodologies, for lightweight methodologies need some interaction with the clients, sometimes little training.
  6. Traditional techniques use in heavyweight methodologies like the waterfall model. However, for lightweight methodologies use agile software development (ASD), FDD etc.
  7. Heavyweight methodologies focus on process not more commutation with clients.
  8. Testing is not done parallelly with development phage in case of Heavyweight methodologies but for lightweight methodologies it dose.
  9. Need Long-term maintenance for heavyweight methodologies software.

These are some important difference between Heavyweight methodologies and lightweight methodologies.

Scrum is a lightweight management process

In software application development, agile software development (ASD) is a methodology for the innovative process that predicts require for pliability and applies a level of pragmatism into the delivery of the finished product. Agile software development emphasis on making code easy, testing and delivering working bits of the application as soon as they are completed.

It is a movement within the Software Development community, It is far away from traditional old process-heavy methodologies and toward the new “relatively lightweight, more effective, human-powered software-development techniques”. Ti generally requires 7 to 10 team members. The Agile Alliance was established in 2001 to encourage the idea of agile software development,

Top methodologies used under the Agile framework are Scrum and extreme programming (XP)

These are the important concept about Agile to develop a project

1.Individuals and interactions over processes and tools

2.Working software over comprehensive documentation

3. Customer collaboration over contract negotiation

4. Responding to change over following a plan

For this problem, instead of int –> use uint- unsigned integers that range from 0

Question: For this problem, instead of int –> use uint- unsigned integers that range from 0 to uint.MaxValue. Do not use the checked keyword.

Your new job as a Computational Physicist involves calculations using very large integers. However, some of the results are incorrect. For example, when adding very large positive integers, sometimes the results are wrong. After consulting with a Computer Science professor for a large fee :). you have determined in some cases the results are too large to fit into an integer.

  1. Write a static method called addBigNumbers that adds two integers and returns the results. If the result is too large to fit into uint.MaxValue, throw an error. Hint: How can you tell if the result is too large to fit? The result will always be <= unit.MaxValue even if it is too large to fit!
  2. Test the method in the main routine using values (i) that fit and (ii) values that result in a sum that is too large to fit. Make sure that the main routine doesn’t crash by adding try and catch blocks. To help, use the following code in main

For(unit i=unit.maxValue/2 – 3;i<unit.MaxValue/2 +3; i++)




Console.WriteLine(i+” + “+i);
uint res=addBigNumbers(i,i);
catch(Exception e)





using System;

namespace addBigNumbersConsole
class Program
static void Main(string[] args)
for(uint i=uint.MaxValue/2-3;i<uint.MaxValue/2+3;i++)
Console.WriteLine(i+” + “+i);
uint res=addBigNumbers(i,i);
if (res == 0 || res==2)
throw new System.ArgumentException(“Values are higher than the maximum capacity of uint”);
catch(Exception e)



static uint addBigNumbers(uint i, uint j)
uint sum = i + j;
return sum;


Calculate the percentage of pyridine ( C5H5N) that forms pyridinium ion

Question: Calculate the percentage of pyridine ( C5H5N) that forms pyridinium ion, C5H5NH+ , in a 0.10 M aqueous solution of pyridine (Kb = 1.7×10-9). Please Explain how ! i dont get it at all !! please help !

Solution: Concepts and reason

The concept used to solve this problem is determining the ratio between present hydroxide ion concentration and total base concentration. Fundamentals

The percentage ionization of any base is calculated as follows:

The chemical equation and equilibrium constant expression for Pyridine is as follows:


According to the problem;

base dissociation or equilibrium constant

Therefore for the weak base calculate the

by using the following formula:

is the concentration of base and is the equilibrium constant for base.

Now Find out; Percentage ionization =?

Now we calculate the percentage ionization:

Thus, in the given solution of pyridine there is 0.013% ammonium ions are present.

The percentage ionization is given by following expression:

Thus, in the given solution of pyridine there is 0.013% ammonium ions are present.

Consider the Finite Automaton represented by the following table

Question: Consider the Finite Automaton represented by the following table.

Prove, by induction on the string length, that this FA accepts every string in which a occurs an odd number of times.


The finite state diagram for above given is :

Here, 1 is the initial state and 2 is the final state

Now, for string s = a

from 1 we reach to 2 and our string is accepted

Now for string s = aa

form 1 we reach 2 and from 2 on a we reach 1 which is a non final state and hence the string is not accepted.

Now for string s = aaa

from 1 on a we reach 2, from 2 on a we reach 1 and form 1 on a we reach 2 and then our string gets accepted.

And so goes on.

So, we finally see that, on every odd occurence of a i.e 1, 3, 5, 7,9,….. our string gets accepted. and for every even occurence of a i.e 2, 4, 6,8,….our string is not accepted.

Hence, through induction we have proved that this finite state accepts every odd occurrences of a as string.

A 10kW, 400 V, 3-phase, 4-pole, 50 Hz delta-connected induction motor is running

Question: A 10kW, 400 V, 3-phase, 4-pole, 50 Hz delta-connected induction motor is running at no load with a line current of 8 A and an input power of 660 watts. At full load, the line current is 18 A and the input power is 11.20 kW. Statoir effective resistance per phase is 1.2 Ω and friction, windage loss is 420 watts. For negligible rotor ohmic losses at no load, calculate

(a) stator core loss (

b)total rotor losses at full load;

(c) al rotor ohmic losses at full load

(d) full load speed

(e) internal torque, shaft torque and motor efficiency.