The probability that a student graduating from West Texas A&M University has student loans to pay off after graduation is 0.60. If two students are randomly selected from this university, what is the probability (rounded to the nearest two decimal places) that neither of them has student loans to pay off after graduation?

The following table gives the frequency distribution of the number of telephones owned by a sample of 50 households selected from a city.

Number of Telephones Owned   Frequency (f)
0   3
1   20
2   14
3   3
4   10
The relative frequency of the first class, rounded to two decimal places, is:

The temperatures (in degrees Fahrenheit) observed during selected seven days of summer in Los Angeles are:

78 99 68 91 105 75 85

The standard deviation, rounded to two decimal places, of these temperatures is:

The ages of all high school teachers in New York state have a bell-shaped distribution with a mean of 39 years and a standard deviation of 7 years. According to the empirical rule, the percentage of teachers in this state who are 32 to 46 years old is approximately:

The waiting times (in minutes) for 11 customers at a supermarket are:

14 9 15 4 4 7 9 11 14 2 6

The percentile rank for the customer who waited 11 minutes is 64%. Give a brief interpretation of this percentile rank.

A specialist electronics company carries out its own repairs. The manager of the repair center is becoming concerned that the cost of repairs is continually increasing. She has observed the operations of the repair center and collected data relating to the number of items being repaired each day, and also the cost of repairing these items over a 50-day period. This information is presented in the following tables:

Use the following series of random numbers to simulate the number and total daily cost of repairs carried out by the department over a 5-day period. Use the following random numbers in order (from left to right) for the simulation of repairs per day:

Use the following random numbers in order (from left to right, first row first - as you need them) for the simulation of the cost of repairs:

Please note you may find that you do not need all of the last sequence of 24 random numbers.


What is the total cost of repairs after 5 days of simulation?

Steinberg Corporation and Dietrich Corporation are identical firms except that Dietrich is more levered. Both companies will remain in business for one more year. The companies' economists agree that the probability of the continuation of the current expansion is 70 percent for the next year and the probability of a recession is 30 percent. If the expansion continues, each firm will generate earnings before interest and taxes (EBIT) of $4.3 million. If a recession occurs, each firm will generate earnings before interest and taxes (EBIT) of $1.7 million. Steinberg's debt obligation requires the firm to pay $970,000 at the end of the year. Dietrich's debt obligation requires the firm to pay $1.8 million at the end of the year. Neither firm pays taxes. Assume a discount rate of 12 percent.

South Central Airlines operates a commuter flight between Atlanta and Charlotte. The plane holds 30 passengers, and the airline makes a $100 profit on each passenger on the flight. When South Central takes 28 reservations for the flight, experience has shown that, on average, two passengers do not show up. As a result, with 30 reservations, South Central is averaging 28 passengers with a profit of 28(100) = $2,800 per flight. The airline operations office has asked for an evaluation of an overbooking strategy in which the airline would accept 32 reservations even though the airplane holds only 30 passengers. The probability distribution for the number of passengers showing up when 32 reservations are accepted is as follows:

The airline will receive a profit of $100 for each passenger on the flight, up to the capacity of 30 passengers. The airline will also incur a cost for any passenger denied seating on the flight. This cost covers added expenses of rescheduling the passenger as well as loss of goodwill, estimated to be $150 per passenger. Develop a worksheet model that will simulate the performance of the overbooking system. Simulate the number of passengers showing up for each of 500 flights by using the VLOOKUP function. Use the results to compute the profit for each flight.

A. What is the mean profit per flight if overbooking is implemented? Round your answer to the nearest dollar.

Over $   

In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities.

It is estimated that 3.5% of the general population will live past their 90th birthday. In a graduating class of 759 high school seniors, find the following probabilities. (Round your answers to four decimal places.)

(a) 15 or more will live beyond their 90th birthday


(b) 30 or more will live beyond their 90th birthday


(c) between 25 and 35 will live beyond their 90th birthday


(d) more than 40 will live beyond their 90th birthday

In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities.

Ocean fishing for billfish is very popular in the Cozumel region of Mexico. In the Cozumel region about 47% of strikes (while trolling) resulted in a catch. Suppose that on a given day a fleet of fishing boats got a total of 27 strikes. Find the following probabilities. (Round your answers to four decimal places.)

(a) 12 or fewer fish were caught


(b) 5 or more fish were caught


(c) between 5 and 12 fish were caught

Based on long experience, an airline found that about 6% of the people making reservations on a flight from Miami to Denver do not show up for the flight. Suppose the airline overbooks this flight by selling 263 ticket reservations for an airplane with only 255 seats.

(a) What is the probability that a person holding a reservation will show up for the flight?


(b) Let n = 263 represent the number of ticket reservations. Let r represent the number of people with reservations who show up for the flight. What expression represents the probability that a seat will be available for everyone who shows up holding a reservation?

P(r ≥ 263)P(r ≤ 263)    P(r ≥ 255)P(r ≤ 255)

(c) Use the normal approximation to the binomial distribution and part (b) to answer the following question: What is the probability that a seat will be available for every person who shows up holding a reservation? (Round your answer to four decimal places.)

One environmental group did a study of recycling habits in a California community. It found that 74% of the aluminum cans sold in the area were recycled. (Use the normal approximation. Round your answers to four decimal places.)

(a) If 384 cans are sold today, what is the probability that 300 or more will be recycled?


(b) Of the 384 cans sold, what is the probability that between 260 and 300 will be recycled?

An important economic problem associated with monopolies is that, at the profit-maximizing equilibrium rate of output, resources are

there are no economic problems re monopolies; it's all in your head

wasted and firms always charge any price (typically the highest possible) they want

underallocated (i.e., not enough is being made) because marginal cost exceeds price

underallocated because price exceeds marginal cost

overallocated (1.e., too much is being made) because price exceeds marginal cost

The demand curve facing a firm will be more elastic,

the more differentiated the product

the larger the economic profit

if there are barriers to entry

the fewer the substitutes there are for its product

the greater the number of firms

Which of the following basically gives monopolistic competitors "market power"?

the ability to charge different prices to different consumers

the ability to differentiate its product from other firms in the market

nothing, because monopolistic competitors are price takers with no market power

barriers to entry

a downward sloping demand curve

Complete the 2nd table below by supplementing the data from the first table. Create 13 classes/groups using
7 as the class interval. The lowest value of the first class/group is the lowest value of the given set of data.
Thus the class mark of the first class is 10. The last class, class 13th, is from 91 to 97.

This data is a sample. The variance of this sample grouped data is 764.4   

Find the following: Mean using Short Method, Mode, SKP, SKB, SKK, Five number summary (Lowest and
highest value from the ungrouped data and Quartiles of the grouped data), normality and the outliers.




















X Values
25 38 44 94
65 61 55 92
56 65 21 78
22 60 88 87
18 44 41 8
96 10 32 8
42 84 8 44
96 54 21 63
7 63 25 40
47 87 39 80

True or False

1. Ceramics often fracture below their theoretical strength due to cracks which concentrate the applied stress.

2. The interstitial diffusion coefficient for a small atom diffusing in a metal is usually larger than its diffusion coefficient via a vacancy mechanism.

3. BCC, HCP, FCC are all Bravais lattices belonging to the cubic crystal system.

4. The larger the number of slip systems available to a metal, the easier it is to deform.

5. HCP has an "abab" stacking sequence, FCC has an "abcabc" stacking sequence.

6. Dislocations move most easily in a crystal along the highest density planes along the lowest density direction.

7. There are 14 Bravais lattices, each of which belongs to one of the 7 crystal systems.

8. Elastic deformation results from the breaking and reforming of bonds.

9. Thermal expansion in crystalline materials is the result of an asymmetry in the repulsive and attractive force curves between pairs of atoms.

10.Graphite and diamond are two different phases of carbon.

The station manager of a local television is interested in predicting the amount of television (in hours) that people will watch in the viewing area. The explanatory variables are: x1 age (in years), x2 education (highest level obtained, in years) and x3 family size (number of family members in household). The multiple regression output is shown below: Summary measures

Multiple R 0.8440

R-Square 0.7123

Adj R-Square 0.6644

StErr of Estimate 0.5598

ANOVA table

Source     df ss            ms       F          p-value

Explained 3 13.9682    4.6561 14.8564 0.0000

Unexplained 18 5.6413 0.3134

Regression coefficients

            Coeff    std err     t-value   p-value

Constant 1.683   1.1696   1.4389 0.1674

Age    -0.0498   0.0199   -2.5018 0.0222

Education 0.2135 0.0503   4.2426 0.0005

Family size 0.0405 0.0784 0.5168 0.6116

Based on the information above to estimate the linear regression model, indicate if the following statement is true or false: “older people watch less television.”