Answers for Exam Practice Questions

[Gabriel Bowers]

Hi everyone,

I've created a google doc with my answers to the past exam questions. 

 

The TA yesterday listed the questions that she felt were relavent to the midterm.  I've listed the names for all of them in the attached google document but there are two that I have not yet done (XILINX, Woodroffe). 

 

I think my answers are correct.  But please add your answers to the document if they are different or any clarification that I've missed out. 

 

The permissions allow anyone with the link below to edit the google document.

 

Good luck studying!

Gabriel

 

Answers for old exam problems - midterm related questions.docx - https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOpwKMSqT9e00/edit?hl=en&authkey=CMqz4pAE

[Carla Nunes]

Thanks for the summary, Gabriel.

 

My answers are very similar to yours.  The differences that I have are listed below.  The rest looks the same!

 

Golden Gate Bridge: 

a) Ep = -0.08

b) My inverse demand function is:  P = 12.68 - 0.0002 * Q, that gives me Q = 31700, and P = 6.34.

 

Bus Transportation:

Have not done yet.

 

IPEX:

Ep = -0.51, solved for %deltaQ = Ep*%deltaP + Ea*%deltaA, where %deltaQ = 0.24, %deltaQ = -0.21, %deltaA =0.083, Ea = 1.5

 

See ya,

Carla

[Carla Nunes]

Oh, forgot to add the XyLink one:

a) Ax: 1% increase in XyLink's adverstising outlays will reduce qty demanded of Unico's product by 2%

    D: When Unico product was launched, demand was 80% higher than in other months

b) 3.7% increase in Au

c) 6.24% price reduction

Carla

[Spencer]

Small mistake on the bart question. For c it should be 0.94 not 0.96. The answer is still right.

Sent from my iPhone

[Gabriel Bowers]

Just going off of memory...

We get the Q ($20m/year) for the $1.25 fares.  You can use this to figure out the revenue per day.  You can use this along with the delta revenue for $1 to figure out the Q for the $1 fare.

Gabriel

On Mon, Feb 21, 2011 at 9:12 AM, Spencer <sph...@gmail.com> wrote:

For golden gate,

How did you find out values for both quantities? One of them is 20 mill divided by 365, how do you find the other one?

Sent from my iPhone

[Spencer]

For golden gate,

How did you find out values for both quantities? One of them is 20 mill divided by 365, how do you find the other one?

Sent from my iPhone

[Spencer]

Hey Gabriel,

Can you show me your calculations for crude oil?

Sent from my iPhone

[Carla Nunes]

Yes, I did the same way.

 

P0 = 1.25

Q0 = 20 mi/365 = 54,794 (per day)

R0 = P0 * Q0 = 68,492.5

 

P1 = 1

Q1 = ?

R1 = R0 - 12,500 = 55,992.5

 

Now u have R1, P1, you can get Q1.

[Spencer]

Also, just to confirm, we will memorize all the equations?

Sent from my iPhone

[Carla Nunes]

I think so... we can't take any cheat sheet w/ us.

 

I will just memorize the ones we have used in the practice problems... I think they are more than enough to answer most of the questions.  I hope!  :)

[zhouz...@yahoo.com]

hi, Carla, for XyLink the coefficient of D does 80% higher
demand come from Exp(.59)=1.8 , then 1.8-1 =0.8 higher ? for
crude oil how do you get EP ranges -0.21~-0.8 , the hint said it's
a number btw 6 and 7 .

On Feb 21, 11:52 am, Carla Nunes <ccrnu...@gmail.com> wrote:
> I think so... we can't take any cheat sheet w/ us.
>
> I will just memorize the ones we have used in the practice problems... I
> think they are more than enough to answer most of the questions.  I hope!
> :)
>
>
>
> On Mon, Feb 21, 2011 at 11:45 AM, Spencer <sphs...@gmail.com> wrote:
> >  Also, just to confirm, we will memorize all the equations?
>
> > Sent from my iPhone
>

> > On Feb 21, 2011, at 11:34 AM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >   Yes, I did the same way.
>
> > P0 = 1.25
> > Q0 = 20 mi/365 = 54,794 (per day)
> > R0 = P0 * Q0 = 68,492.5
>
> > P1 = 1
> > Q1 = ?
> > R1 = R0 - 12,500 = 55,992.5
>
> > Now u have R1, P1, you can get Q1.
>

> > On Mon, Feb 21, 2011 at 9:45 AM, Gabriel Bowers <gabrielbow...@gmail.com>wrote:
>
> >> Just going off of memory...
> >> We get the Q ($20m/year) for the $1.25 fares.  You can use this to figure
> >> out the revenue per day.  You can use this along with the delta revenue for
> >> $1 to figure out the Q for the $1 fare.
> >> Gabriel

> >>   On Mon, Feb 21, 2011 at 9:12 AM, Spencer <sphs...@gmail.com> wrote:
>
> >>>  For golden gate,
>
> >>> How did you find out values for both quantities? One of them is 20 mill
> >>> divided by 365, how do you find the other one?
>
> >>> Sent from my iPhone
>

> >>> On Feb 20, 2011, at 2:24 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>>   Oh, forgot to add the XyLink one:
> >>> a) Ax: 1% increase in XyLink's adverstising outlays will reduce qty
> >>> demanded of Unico's product by 2%
> >>>     D: When Unico product was launched, demand was 80% higher than in
> >>> other months
> >>> b) 3.7% increase in Au
> >>> c) 6.24% price reduction
> >>> Carla

> >>> On Sun, Feb 20, 2011 at 2:17 PM, Carla Nunes < <ccrnu...@gmail.com>
> >>> ccrnu...@gmail.com> wrote:
>
> >>>> Thanks for the summary, Gabriel.
>
> >>>> My answers are very similar to yours.  The differences that I have are
> >>>> listed below.  The rest looks the same!
>
> >>>> Golden Gate Bridge:
> >>>> a) Ep = -0.08
> >>>> b) My inverse demand function is:  P = 12.68 - 0.0002 * Q, that gives me
> >>>> Q = 31700, and P = 6.34.
>
> >>>> Bus Transportation:
> >>>> Have not done yet.
>
> >>>> IPEX:
> >>>> Ep = -0.51, solved for %deltaQ = Ep*%deltaP + Ea*%deltaA, where %deltaQ
> >>>> = 0.24, %deltaQ = -0.21, %deltaA =0.083, Ea = 1.5
>
> >>>> See ya,
> >>>> Carla
>

> >>>> On Sun, Feb 20, 2011 at 11:52 AM, Gabriel Bowers <<gabrielbow...@gmail.com>
> >>>> gabrielbow...@gmail.com> wrote:
>
> >>>>> Hi everyone,
>

> >>>>> I've created a google doc with *my answers* to the past exam

> >>>>> questions.
>
> >>>>> The TA yesterday listed the questions that she felt were relavent to
> >>>>> the midterm.  I've listed the names for all of them in the attached google
> >>>>> document but there are two that I have not yet done (XILINX, Woodroffe).
>
> >>>>> I think my answers are correct.  But please add your answers to the
> >>>>> document if they are different or any clarification that I've missed out.
>
> >>>>> The permissions allow anyone with the link below to edit the google
> >>>>> document.
>
> >>>>> Good luck studying!
> >>>>> Gabriel
>
> >>>>> Answers for old exam problems - midterm related questions.docx -

> >>>>> <https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...>
> >>>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...- Hide quoted text -
>
> - Show quoted text -

[Carla Nunes]

I'm out right now. As soon as I get back home, I'll respond with details.

Sent from my iPhone

[Carla Nunes]

Hi,

 

Yes, so for the XYLink you do get the exponential of 0.59, which is 1.8, so when you transform into a linear function, you will end up with 1.80^D.  When D = 1, you have a multiplier of 1.8, wich is 80%.

 

For the crude oil one, I got 6.48 for the arc elasticity using P0 = 40, P1 = 34.50, Q0 = 1,700,000, Q1 = 600,000. 

Let me know if you have more questions.

 

Carla

[Spencer]

How did you calculate ep for demand for gas in France?

Sent from my iPhone

[Spencer]

Couple questions,

For golden gate bridge, how'd you solve for a after you found out b? What values did you plug in for p an q?

For demand for gas in France,

How did you get ep after you get ey?

What were your steps for b and c for the xylink?

Sent from my iPhone

[Carla Nunes]

Golden gate:

You have the formula Q = a + bP, you have Q, P combination from part a (you can choose P0, Q0 for example), you found b from the slope, then you can plug in on this formula to find a.

 

Gas in France:

I forgot to do this one, I'll let you know when done.

XYlink:

For part b, you use the %deltaQ = EAu*%deltaAu + EPu*%deltaPu => 10% = 1.4*%deltaAu - 1.2*4%

For part c, -10% = 1.6*%deltaPx

 

[Spencer Hsu]

what'd you guys get for advanced tech letter A? 

On Mon, Feb 21, 2011 at 4:03 PM, Carla Nunes <ccrn...@gmail.com> wrote:

Golden gate:

You have the formula Q = a + bP, you have Q, P combination from part a (you can choose P0, Q0 for example), you found b from the slope, then you can plug in on this formula to find a.

 

Gas in France:

I forgot to do this one, I'll let you know when done.

XYlink:

For part b, you use the %deltaQ = EAu*%deltaAu + EPu*%deltaPu => 10% = 1.4*%deltaAu - 1.2*4%

For part c, -10% = 1.6*%deltaPx

 

On Mon, Feb 21, 2011 at 3:49 PM, Spencer <sph...@gmail.com> wrote:

Couple questions,for SF ballet

[Spencer Hsu]

Nevermind, I got my units wrong.

[zhouz...@yahoo.com]

hi , for gas in france I think Ey=1.25 my answer is 0.21=1.25*
(2.31-1)+EP (3-1) EP= -.71 for part 2 I am not sure if we should
directly add the EP0 to EP ,hope someone help~

On Feb 21, 6:43 pm, Spencer Hsu <sphs...@gmail.com> wrote:
> Nevermind, I got my units wrong.
>
>
>
> On Mon, Feb 21, 2011 at 6:42 PM, Spencer Hsu <sphs...@gmail.com> wrote:
> > what'd you guys get for advanced tech letter A?
>

> > On Mon, Feb 21, 2011 at 4:03 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >> Golden gate:
> >> You have the formula Q = a + bP, you have Q, P combination from part a
> >> (you can choose P0, Q0 for example), you found b from the slope, then you
> >> can plug in on this formula to find a.
>
> >> Gas in France:
> >> I forgot to do this one, I'll let you know when done.
>
> >> XYlink:
> >> For part b, you use the %deltaQ = EAu*%deltaAu + EPu*%deltaPu => 10% =
> >> 1.4*%deltaAu - 1.2*4%
> >>  For part c, -10% = 1.6*%deltaPx
>

> >> On Mon, Feb 21, 2011 at 3:49 PM, Spencer <sphs...@gmail.com> wrote:
>
> >>>  Couple questions,for SF ballet
>
> >>> For golden gate bridge, how'd you solve for a after you found out b? What
> >>> values did you plug in for p an q?
>
> >>> For demand for gas in France,
> >>> How did you get ep after you get ey?
>
> >>> What were your steps for b and c for the xylink?
>
> >>> Sent from my iPhone
>

> >>> On Feb 21, 2011, at 2:54 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>>   Hi,
>
> >>> Yes, so for the XYLink you do get the exponential of 0.59, which is 1.8,
> >>> so when you transform into a linear function, you will end up with 1.80^D.
> >>> When D = 1, you have a multiplier of 1.8, wich is 80%.
>
> >>> For the crude oil one, I got 6.48 for the arc elasticity using P0 = 40,
> >>> P1 = 34.50, Q0 = 1,700,000, Q1 = 600,000.
> >>> Let me know if you have more questions.
>
> >>> Carla

> >>> On Mon, Feb 21, 2011 at 2:15 PM, Carla Nunes < <ccrnu...@gmail.com>
> >>> ccrnu...@gmail.com> wrote:
>
> >>>> I'm out right now.  As soon as I get back home, I'll respond with
> >>>> details.
>
> >>>> Sent from my iPhone
>

> >>>> On Feb 21, 2011, at 12:56 PM, " <zhouziha...@yahoo.com>
> >>>> zhouziha...@yahoo.com" < <zhouziha...@yahoo.com>zhouziha...@yahoo.com>

> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp
> >>>> ...>
>
> >>>> <https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...>
> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...
> >>>> Hide quoted text -
>
> >>>> >> - Show quoted text -- Hide quoted text -

[zhouz...@yahoo.com]

btw , how to interprete RMSE of problem Woodruff if we are also
given MAPE ,how to interprete them respectively?

On Feb 21, 6:43 pm, Spencer Hsu <sphs...@gmail.com> wrote:

> Nevermind, I got my units wrong.
>
>
>
> On Mon, Feb 21, 2011 at 6:42 PM, Spencer Hsu <sphs...@gmail.com> wrote:
> > what'd you guys get for advanced tech letter A?
>

> > On Mon, Feb 21, 2011 at 4:03 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >> Golden gate:
> >> You have the formula Q = a + bP, you have Q, P combination from part a
> >> (you can choose P0, Q0 for example), you found b from the slope, then you
> >> can plug in on this formula to find a.
>
> >> Gas in France:
> >> I forgot to do this one, I'll let you know when done.
>
> >> XYlink:
> >> For part b, you use the %deltaQ = EAu*%deltaAu + EPu*%deltaPu => 10% =
> >> 1.4*%deltaAu - 1.2*4%
> >>  For part c, -10% = 1.6*%deltaPx
>

> >> On Mon, Feb 21, 2011 at 3:49 PM, Spencer <sphs...@gmail.com> wrote:
>
> >>>  Couple questions,for SF ballet
>
> >>> For golden gate bridge, how'd you solve for a after you found out b? What
> >>> values did you plug in for p an q?
>
> >>> For demand for gas in France,
> >>> How did you get ep after you get ey?
>
> >>> What were your steps for b and c for the xylink?
>
> >>> Sent from my iPhone
>

> >>> On Feb 21, 2011, at 2:54 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>>   Hi,
>
> >>> Yes, so for the XYLink you do get the exponential of 0.59, which is 1.8,
> >>> so when you transform into a linear function, you will end up with 1.80^D.
> >>> When D = 1, you have a multiplier of 1.8, wich is 80%.
>
> >>> For the crude oil one, I got 6.48 for the arc elasticity using P0 = 40,
> >>> P1 = 34.50, Q0 = 1,700,000, Q1 = 600,000.
> >>> Let me know if you have more questions.
>
> >>> Carla

> >>> On Mon, Feb 21, 2011 at 2:15 PM, Carla Nunes < <ccrnu...@gmail.com>
> >>> ccrnu...@gmail.com> wrote:
>
> >>>> I'm out right now.  As soon as I get back home, I'll respond with
> >>>> details.
>
> >>>> Sent from my iPhone
>

> >>>> On Feb 21, 2011, at 12:56 PM, " <zhouziha...@yahoo.com>
> >>>> zhouziha...@yahoo.com" < <zhouziha...@yahoo.com>zhouziha...@yahoo.com>

> >>>> >>>>>>> <<https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp..>
> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp
> >>>> ...>
>
> >>>> <https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...>
> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...

> >>>> Hide quoted text -
>
> >>>> >> - Show quoted text -- Hide quoted text -

[Kevin]

Cigarettes,

In part B why is .29%, and .08% for price and advertising. But 10%
for the cancer society. It seems like the others should be 29% and 8%
respectively or .1% for the cancer society effect.




Kevin

On Feb 21, 6:42 pm, Spencer Hsu <sphs...@gmail.com> wrote:
> what'd you guys get for advanced tech letter A?
>
>
>
>
>
>
>
> On Mon, Feb 21, 2011 at 4:03 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
> > Golden gate:
> > You have the formula Q = a + bP, you have Q, P combination from part a (you
> > can choose P0, Q0 for example), you found b from the slope, then you can
> > plug in on this formula to find a.
>
> > Gas in France:
> > I forgot to do this one, I'll let you know when done.
>
> > XYlink:
> > For part b, you use the %deltaQ = EAu*%deltaAu + EPu*%deltaPu => 10% =
> > 1.4*%deltaAu - 1.2*4%
> >  For part c, -10% = 1.6*%deltaPx
>

> > On Mon, Feb 21, 2011 at 3:49 PM, Spencer <sphs...@gmail.com> wrote:
>
> >>  Couple questions,for SF ballet
>
> >> For golden gate bridge, how'd you solve for a after you found out b? What
> >> values did you plug in for p an q?
>
> >> For demand for gas in France,
> >> How did you get ep after you get ey?
>
> >> What were your steps for b and c for the xylink?
>
> >> Sent from my iPhone
>

> >> On Feb 21, 2011, at 2:54 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>   Hi,
>
> >> Yes, so for the XYLink you do get the exponential of 0.59, which is 1.8,
> >> so when you transform into a linear function, you will end up with 1.80^D.
> >> When D = 1, you have a multiplier of 1.8, wich is 80%.
>
> >> For the crude oil one, I got 6.48 for the arc elasticity using P0 = 40, P1
> >> = 34.50, Q0 = 1,700,000, Q1 = 600,000.
> >> Let me know if you have more questions.
>
> >> Carla

> >> On Mon, Feb 21, 2011 at 2:15 PM, Carla Nunes < <ccrnu...@gmail.com>
> >> ccrnu...@gmail.com> wrote:
>
> >>> I'm out right now.  As soon as I get back home, I'll respond with
> >>> details.
>
> >>> Sent from my iPhone
>

> >>> On Feb 21, 2011, at 12:56 PM, " <zhouziha...@yahoo.com>
> >>> zhouziha...@yahoo.com" < <zhouziha...@yahoo.com>zhouziha...@yahoo.com>

> >>> >>>>>>> <<https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp..>
> >>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp
> >>> ...>
>
> >>> <https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...>
> >>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...

[Carla Nunes]

No, 20 million is the number of tolls collected, so it is Q rather than Revenue.

On Tue, Feb 22, 2011 at 4:04 PM, Kevin <jo.k...@gmail.com> wrote:

Carla,

Question for golden gate don't you have to take the 54,794 and divide
by 1.25 to get quantity?  it seems like 54,794 should be revenue....



Kevin

On Feb 21, 11:34 am, Carla Nunes <ccrnu...@gmail.com> wrote:
> Yes, I did the same way.
>
> P0 = 1.25
> Q0 = 20 mi/365 = 54,794 (per day)
> R0 = P0 * Q0 = 68,492.5
>
> P1 = 1
> Q1 = ?
> R1 = R0 - 12,500 = 55,992.5
>
> Now u have R1, P1, you can get Q1.
>

> On Mon, Feb 21, 2011 at 9:45 AM, Gabriel Bowers <gabrielbow...@gmail.com>wrote:

>
>
>
>
>
>
>
> > Just going off of memory...
> > We get the Q ($20m/year) for the $1.25 fares.  You can use this to figure
> > out the revenue per day.  You can use this along with the delta revenue for
> > $1 to figure out the Q for the $1 fare.
> > Gabriel

> >   On Mon, Feb 21, 2011 at 9:12 AM, Spencer <sphs...@gmail.com> wrote:
>
> >>  For golden gate,
>
> >> How did you find out values for both quantities? One of them is 20 mill
> >> divided by 365, how do you find the other one?
>
> >> Sent from my iPhone
>

> >> On Feb 20, 2011, at 2:24 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>   Oh, forgot to add the XyLink one:
> >> a) Ax: 1% increase in XyLink's adverstising outlays will reduce qty
> >> demanded of Unico's product by 2%
> >>     D: When Unico product was launched, demand was 80% higher than in
> >> other months
> >> b) 3.7% increase in Au
> >> c) 6.24% price reduction
> >> Carla

> >> On Sun, Feb 20, 2011 at 2:17 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>> Thanks for the summary, Gabriel.
>
> >>> My answers are very similar to yours.  The differences that I have are
> >>> listed below.  The rest looks the same!
>
> >>> Golden Gate Bridge:
> >>> a) Ep = -0.08
> >>> b) My inverse demand function is:  P = 12.68 - 0.0002 * Q, that gives me
> >>> Q = 31700, and P = 6.34.
>
> >>> Bus Transportation:
> >>> Have not done yet.
>
> >>> IPEX:
> >>> Ep = -0.51, solved for %deltaQ = Ep*%deltaP + Ea*%deltaA, where %deltaQ =
> >>> 0.24, %deltaQ = -0.21, %deltaA =0.083, Ea = 1.5
>
> >>> See ya,
> >>> Carla
>
> >>> On Sun, Feb 20, 2011 at 11:52 AM, Gabriel Bowers <

> >>> gabrielbow...@gmail.com> wrote:
>
> >>>> Hi everyone,
>
> >>>> I've created a google doc with *my answers* to the past exam

> >>>> questions.
>
> >>>> The TA yesterday listed the questions that she felt were relavent to the
> >>>> midterm.  I've listed the names for all of them in the attached google
> >>>> document but there are two that I have not yet done (XILINX, Woodroffe).
>
> >>>> I think my answers are correct.  But please add your answers to the
> >>>> document if they are different or any clarification that I've missed out.
>
> >>>> The permissions allow anyone with the link below to edit the google
> >>>> document.
>
> >>>> Good luck studying!
> >>>> Gabriel
>
> >>>> Answers for old exam problems - midterm related questions.docx -

> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...

[Carla Nunes]

Hi Christy,

I was working on the France homework, I'm not sure if it's correct though.  This is the formula I ended up with.  It's different from what Gabriel has in his answer sheet.  I sent him an email to find out how he did the calculation.

%∆Q = Ep*∆P + Ey*%∆Y
21 = Ep*200 + 1.25*131 => Ep = -0.71

For part b), you just add the other factor for diesel. 
%∆Q = Ep*∆P + Ey*%∆Y + Ed*%∆D
21 = Ep*200 + 1.25*131 + 0.3*200 => Ep = -1.01

I'm not sure if this is correct.  I'll see if the TA can help.  If someone knows, please share.

Thx,
Carla

On Tue, Feb 22, 2011 at 1:30 PM, Christy Knight <christy...@gmail.com> wrote:

For "Demand for Gasoline in France" -

I understand how to get Ey, and but for Ep, Using the same logic as
Ey: ∆Q/Q / ∆P/P I get .099
If I use the full formula ∆Q/Q = Ep*∆P/P + Ey*∆Y/Y , I am getting Ep
= .00198

help?

[Spencer]

What does the coefficient of d mean in the cigarette function

Sent from my iPhone

[Christy Fairlie]

BTW - I am in the library (probably forever) if anyone wants to join me.

-Christy

[Carla Nunes]

I used what was given -> gasoline consumption increases about one and a quarter percent with each percentage increase in consumer income.

Again, i'm not sure if this is to be used, or if we do the calculation for Ey as Gabriel did.

On Tue, Feb 22, 2011 at 5:41 PM, Spencer <sph...@gmail.com> wrote:

Carla, what values did you use to calculate ey

Sent from my iPhone

[Spencer]

Carla, what values did you use to calculate ey

Sent from my iPhone

On Feb 22, 2011, at 5:37 PM, Christy Fairlie <christy...@gmail.com> wrote:

[Christy Knight]

For "Demand for Gasoline in France" -

I understand how to get Ey, and but for Ep, Using the same logic as
Ey: ∆Q/Q / ∆P/P I get .099
If I use the full formula ∆Q/Q = Ep*∆P/P + Ey*∆Y/Y , I am getting Ep
= .00198

help?


On Feb 21, 7:12 pm, Kevin <jo.ke...@gmail.com> wrote:

[Kevin]

Ad Tech

Can anyone explain how to get to the pricing equation?


Q = -86100 – 10.1P + 300.7Y + 24.1A

Solve for pricing equation: P = (1/10.1) (6520 – Q).

[Spencer Hsu]

Gasoline has gone up 1.21, and consumer has gone up 2.31. How did you only get 1.25 and 1%? Am I looking at the wrong problem?

[Rob Sidhu]

I'm not sure how that equation was derived, but here's what I got and the final answers match Gabe's:

Q = -86100 - 10.1P +300.7(300) +24.1(1200)
Q = 33030 - 10.1P
Q - 33030 = -10.1P
P = 3270.29 - (1/10.1)Q

Therefore:

R = P x Q
R = 3270.29Q - (1/10.1)Q^2
MR = 3270.29 - (20/101)Q

---

From: Kevin <jo.k...@gmail.com>
To: Econ_401_winter_2011 <econ_401_w...@googlegroups.com>
Sent: Tue, February 22, 2011 8:21:48 PM
Subject: Re: Answers for Exam Practice Questions

[Rob Sidhu]

This is correct; got a confirmation from TA.

---

From: Carla Nunes <ccrn...@gmail.com>
To: econ_401_w...@googlegroups.com
Cc: Christy Knight <christy...@gmail.com>
Sent: Tue, February 22, 2011 5:27:54 PM

Subject: Re: Answers for Exam Practice Questions

[Carla Nunes]

I got the same as Kevin too.

[Carla Nunes]

Sorry, as Rob.  :)

[Christy Fairlie]

Does anyone know what the RMSE actually tells us?  He only shows how to calculate in the regression slides...  and google is no help.

[Carla Nunes]

Standard error of the forecast.

[Kevin]

Carla,

Question for golden gate don't you have to take the 54,794 and divide
by 1.25 to get quantity? it seems like 54,794 should be revenue....



Kevin

> >>>>https://docs.google.com/document/d/1eydhKZ1jli457qapSlUxhLawrqhRTIFOp...

[Gayathri Ravi]

Hi, Can some one please present the calculation for the bus transportation please..don't know what I am doing wrong. Thanks

[Kevin]

On golden gate,

I'm still having trouble figuring out the how to get the optimal
toll. I have values of -.0002 for b and -219,176,000 for a. Not sure
where to go from there.



Kevin

On Feb 22, 11:00 pm, Gayathri Ravi <gay...@gmail.com> wrote:
> Hi, Can some one please present the calculation for the bus transportation
> please..don't know what I am doing wrong. Thanks
>
>
>
>
>
>
>
> On Tue, Feb 22, 2011 at 10:00 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
> > Standard error of the forecast.
>

> > On Tue, Feb 22, 2011 at 9:53 PM, Christy Fairlie <christyfkni...@gmail.com

> > > wrote:
>
> >> Does anyone know what the RMSE actually tells us?  He only shows how to
> >> calculate in the regression slides...  and google is no help.
>
> >> On Feb 22, 2011, at 9:38 PM, Carla Nunes wrote:
>
> >> Sorry, as Rob.  :)
>

> >> On Tue, Feb 22, 2011 at 9:38 PM, Carla Nunes <ccrnu...@gmail.com> wrote:
>
> >>> I got the same as Kevin too.
>

> >>> On Tue, Feb 22, 2011 at 8:42 PM, Rob Sidhu <rob_sid...@yahoo.com> wrote:
>
> >>>> I'm not sure how that equation was derived, but here's what I got and
> >>>> the final answers match Gabe's:
>
> >>>> Q = -86100 - 10.1P +300.7(300) +24.1(1200)
> >>>> Q = 33030 - 10.1P
> >>>> Q - 33030 = -10.1P
> >>>> P = 3270.29 - (1/10.1)Q
>
> >>>> Therefore:
>
> >>>> R = P x Q
> >>>> R = 3270.29Q - (1/10.1)Q^2
> >>>> MR = 3270.29 - (20/101)Q
>

> >>>> ------------------------------
> >>>> *From:* Kevin <jo.ke...@gmail.com>
> >>>> *To:* Econ_401_winter_2011 <econ_401_w...@googlegroups.com>
> >>>> *Sent:* Tue, February 22, 2011 8:21:48 PM
> >>>> *Subject:* Re: Answers for Exam Practice Questions

> ...
>
> read more »

[Savita Raina]

Hey Kevin,

 

Even I am confused with this problem

 

This is how i did

 

Yearly revenue when price was 1.25 is 20 million

Daily revenue R1 = 20000000/365 = 54794.521 ~ 54794

Q1 = R1/P1 = 54794/1.25  = 43835.2 ~ 43835

 

R2 – R1 = -12500

R2 – 54794 = -12500

R2 = 42294

Q2 = R2/P2 = 42294/1 = 42294

 

E_p = (dQ/dP)(P/Q) = ((Q2-Q1)/(P2-P1))(P/Q) = ((42294-43835)/(1-1.25))(1/42294) = 0.145

b) Since my demand function is like Q = a+bP

I took derivative dQ/ dP = b

which from above calculation = 6164

Therefore my equation is              Q = a +6164 P

Number of crossings at  P2 = $1 Q2 = 42294

=> a = 6.86

Now my eqn Q = 6.86 + 6164 P

 

therefore revenue = P*Q = [ Q - 6.86]/ 6164 *[ Q]

 

Did any of you solve this problem this way.

 

Savita

[Savita Raina]

Hey Kevin I finally got the Golden gate problem and here is the solution hoping this is correct:

P1 = $1, R1 = Ro - 12,500

Po = 1.25, Ro = PoQo

Qo = 20/365 = 54794 / day

Ro = 1.25 * 54794 = $ 68,493

--> Now calculate R1

---> Ep = dQ/ dP * (P/Q)

b = dQ/dP = -4796 @ P1= 1, Q1 = 55993

New eqn Q = a - 4796 P ( substitute value of Q and P @ P = $1)

you will get value of a 

and finally eqn  P =12.67 - 2.08 X 10^ -4 Q

 R = P*Q and take derivate  dR/dQ  = 0 (marginal revenue = 0) and find optimal Q and P

If anyone of you find anything wrong with this method plz correct it

Savita

[Gayathri Ravi]

Never mind, I got it. Thanks

[Rob Sidhu]

Can someone let me know what they got for HW 2(ii) - Samtrans?... i am getting en Ep = -.543 and wanted to check this against someone who did it correctly :o)...

---

From: Gayathri Ravi <gay...@gmail.com>
To: econ_401_w...@googlegroups.com
Cc: Carla Nunes <ccrn...@gmail.com>
Sent: Wed, February 23, 2011 7:10:41 AM

[Gayathri Ravi]

Here are the answers for SamTrans

(i) Price Elasticity with p1 = -0.55

(ii) price Elasticity with p2 = -0.71

[Gayathri Ravi]

Is anyone in the campus already to discuss any exam-problems, will be there in 15 minutes.

[alex smirnov]

yes, room 300H

[Adi Aloni]

Good luck everyone, thanks for your support. I was passive this time, my timing was different than everyone else’s, and it was great help.

Adi.

[David Song]

Hope everyone had a good test today. I didn't contribute to the discussion this time because I wasn't planning to take this test. 

David

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