Air flows through a 0.25-m-diameter duct. At the inlet the velocity is 300 m/s, and the stagnation temperature is 90°C. If the Mach number at the exit is 0.3, determine the direction and the rate of heat transfer. For the same conditions at the inlet, determine the amount of heat that must be transferred to the system if the flow is to be sonic at the exit of the duct.
In: Mechanical Engineering
A queue with one server without buffer, the probability of a customer’ arrival and departure in a time unit is p and q respectively. Please try to 1) give the one step state transition probability matrix. 2) give the balance equations. 3) calculate the limiting probabilities for p=0.3 and q=0.5. (12 points)
In: Statistics and Probability
Find the following probabilities
a. P(X = 2) when X ∼ Bin(4,0.6)
b. P(X > 2) when X ∼ Bin(8, 0.5)
c. P(X ≤ 2) when X ∼ Bin(5, 0.5)
d. P(3 ≤ X ≤ 5) when X ∼ Bin(6, 0.3)
In: Statistics and Probability
Stock A has an expected return of 17% and a standard deviation of 29%. Stock B has an expected return of 14% and a standard deviation of 18%. The risk-free rate is 2.8% and the correlation between Stock A and Stock B is 0.3. Build the optimal risky portfolio of Stock A and Stock B. What is the expected return on this portfolio?
In: Finance
The market and Stock A have the following probability distributions:
| Probability | Return on Market | Return on Stock A |
| 0.15 | 15% | 18% |
| 0.3 | 12% | 15% |
| 0.55 | 10% | 11% |
a. Calculate the expected rates of return for the market and Stock A.
b. Calculate the standard deviations for the market and Stock A.
c. Calculate the coefficient of variation for the market and Stock A.
In: Finance
Andi and Budi will meet. Suppose A is an event where Andi arrives late, and B is an event where Budi arrives late, with P (A) = 0.1 and P (B) = 0.3. What is the chance the two of them will meet on time if
a. Genesis A and B are independent
(independent)?
b. P (B | A) = 0.5?
c. P (B | A) = 0.1?
In: Math
One of my recent papers examine important and timely
research questions using a field experiment approach in eBay
auctions: (i) Can merchandise return policy (MRP; liberalness in
the MRP) increase consumers’ willingness to pay? and (ii) is the
marginal impact of MRP diminishing? In this study we created three
brand new eBay seller profiles, all with zip-codes located within
five miles of each other in a college town in the U.S. The eBay
stores received exactly the same product description, pictures,
outbound shipping policies, etc. The only difference among the
three sellers was the extent of liberalness in the MRP and we chose
to operationalize MRP liberalness in terms of the time window
during which the customer is allowed to return the purchased
product. The most conservative MRP (Storefront 1 and 1a) involved a
15-day return window. According to trade publications, this return
condition is more conservative than retail-industry averages.
Storefront2 and 2a received a 30-day return window, which
corresponds closely with retail-industry averages. Finally,
Storefront3 and 3a received a 60-day return window, which is more
liberal than many retailers offer at this point. The other elements
of the return remained constant across the three storefronts.
Therefore, in terms of overall return-policy liberalness, it could
be argued that Storefront1/1a < Storefront 2/2a < Storefront
3/3a . It is important to note that it is very common in my data
that we observe a customer’s bidding behavior in several
auctions.
[Question] During the revision stage of the journal publication
process, one of reviewer’s comment was that the I may use a fixed
effects model to control for unobserved individual fixed effects.
Do you agree or disagree with the above statement? Please explain
with details.
In: Economics
One of my recent papers examine important and timely research questions using a field experiment approach in eBay auctions: (i) Can merchandise return policy (MRP; liberalness in the MRP) increase consumers’ willingness to pay? and (ii) is the marginal impact of MRP diminishing? In this study we created three brand new eBay seller profiles, all with zip-codes located within five miles of each other in a college town in the U.S. The eBay stores received exactly the same product description, pictures, outbound shipping policies, etc. The only difference among the three sellers was the extent of liberalness in the MRP and we chose to operationalize MRP liberalness in terms of the time window during which the customer is allowed to return the purchased product. The most conservative MRP (Storefront 1 and 1a) involved a 15-day return window. According to trade publications, this return condition is more conservative than retail-industry averages. Storefront2 and 2a received a 30-day return window, which corresponds closely with retail-industry averages. Finally, Storefront3 and 3a received a 60-day return window, which is more liberal than many retailers offer at this point. The other elements of the return remained constant across the three storefronts. Therefore, in terms of overall return-policy liberalness, it could be argued that Storefront1/1a < Storefront 2/2a < Storefront 3/3a . It is important to note that it is very common in my data that we observe a customer’s bidding behavior in several auctions.
[Question] During the revision stage of the journal publication process, one of reviewer’s comment was that the I may use a fixed effects model to control for unobserved individual fixed effects. Do you agree or disagree with the above statement? Please explain with details.
In: Economics
Brett and Lisa file taxes under the married filing jointly status. Lisa is a sales manager for an auto parts company and Brett takes care of their 3 children. In 2018, Lisa receives a promotion associated with a move to a new division located over 500 miles from their existing home. The cost to move their household items is $8,700. Lisa's employer reimburses her for $3,000 of those costs and also pays $2,100 for airfare for the entire family to fly to the new destination. Lisa's moving expenses deduction for 2018 is:
a.$5,700
b.$3,600
c.$0
d.$8,700
e.None of these choices are correct.
Ellen supports her family as a self-employed attorney. She reports $90,000 of income on her Schedule C and pays $8,000 for health insurance for her family, $2,500 for dental insurance, $4,000 for health insurance for her 23-year-old daughter who is no longer a dependent, and $3,000 for disability insurance for herself. What is Ellen's self-employed health insurance deduction?
a.$10,500
b.$12,000
c.$13,500
d.$14,500
e.$8,000
Over the years, Monica contributed $15,000 to a Roth IRA opened 10 years ago. The IRA has a current value of $37,500. She is 54 years old and takes a distribution of $25,000. How much of the distribution will be taxable to Monica?
a.$10,000
b.$0
c.$37,500
d.$15,000
e.$25,000
Jody is a physician (not covered by a retirement plan) with a salary of $40,000 from the hospital where she is employed. She supports her husband, Andre, who sells art work and has no earned income. Both are in their twenties. What is the maximum total amount that Jody and Andre may contribute to their IRAs and deduct for the 2018 tax year?
a.$5,000
b.$5,500
c.$11,000
d.$10,000
e.None of these choices are correct.
In: Accounting
Waterbury Insurance Company wants to study the relationship between the amount of fire damage and the distance between the burning house and the nearest fire station. This information will be used in setting rates for insurance coverage. For a sample of 30 claims for the last year, the director of the actuarial department determined the distance from the fire station (x) and the amount of fire damage, in thousands of dollars (y). The MegaStat output is reported below.
| ANOVA table | ||||||
| Source | SS | df | MS | F | ||
| Regression | 1,865.5782 | 1 | 1,865.5782 | 39.56 | ||
| Residual | 1,320.4934 | 28 | 47.1605 | |||
| Total | 3,186.0716 | 29 | ||||
| Regression output | |||
| Variables | Coefficients | Std. Error | t(df=28) |
| Intercept | 13.7523 | 3.0957 | 3.672 |
| Distance–X | 6.3449 | 7.279 | 6.3 |
a-1. Write out the regression equation. (Round your answers to 3 decimal places.)
How much damage would you estimate for a fire 7 miles from the nearest fire station? (Round your answer to the nearest dollar amount.)
c-1. Determine the coefficient of determination. (Round your answer to 3 decimal places.)
c-2. Fill in the blank below. (Round your answer to one decimal place.)
d-1. Determine the correlation coefficient. (Round your answer to 3 decimal places.)
d-3. How did you determine the sign of the correlation coefficient?
e-1. State the decision rule for 0.01 significance level: H0 : ρ = 0; H1 : ρ ≠ 0. (Negative value should be indicated by a minus sign. Round your answers to 3 decimal places.)
e-2. Compute the value of the test statistic for the hypothesis of β1. (Round your answer to 2 decimal places.)
e-3. Is there any significant relationship between the distance from the fire station and the amount of damage? Use the 0.01 significance level.
In: Statistics and Probability