125( Midterm ) house sales will increase in the next 6 months is estimated to be

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125(Midterm)

house sales will increase in the next 6 months is estimated to be 0.25

the interest rates on housing loans will go up in the same period is estimated to be 0.74

house sales or interest rates will go up during the next 6 months is estimated to be 0.89

house sales will increase in the next 6 months is estimated to be 0.25.

the interest rates on housing loans will go up in the same period is estimated to be 0.74

house sales or interest rates will go up during the next 6 months is estimated to be 0.89

Q1. A study is under way in Yosemite National Forest to determine the adult height of American pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains 25,000 adult American pines. The study involves collecting heights from 250 randomly selected adult American pine trees and analyzing the results. Identify the population from which the study was sampled.
    a. The 250 randomly selected adult American pine trees in the forest.
    b. The 25,000 adult American pine trees in the forest.
    c. All the adult American pine trees taller than 60 feet in the world.
    d. All American pine trees, of any age, in the forest.

Q2. When extreme values are present in a set of data, which of the following descriptive summary measures are most appropriate?
    a. CV and range.
    b. mean and standard deviation.
    c. interquartile range and median.
    d. variance and interquartile range.

Q3. The collection of all possible events is called:
    a. a simple probability.
    b. a sample space.
    c. a joint probability.
    d. the null set.

Q4. If two events are mutually exclusive, what is the probability that one or the other occurs?
    a. 0
    b. 0.50
    c. 1.00
    d. Cannot be determined from the information given.

Q5. The Central Limit Theorem is important in statistics because:
    a. for a large n, it says the population is approximately normal.
    b. for any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size.
    c. for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population.
    d. for any sized sample, it says the sampling distribution of the sample mean is approximately normal.

Q6. The process of using sample statistics to draw conclusions about true population parameters is called:
    a. statistical inference.
    b. the scientific method.
    c. sampling.
    d. descriptive statistics.

Q7. A catalog company that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product. The length of time was found to be a random variable best approximated by an exponential distribution with a mean equal to 3 minutes. What proportion of customers having to hold more than 1.5 minutes will hang up before placing an order?
    a. 0.86466
    b. 0.60653
    c. 0.39347
    d. 0.13534

Q8. Given the numbers: 2, 4, 5, 6, 8 what are the median and standard deviation?
    a. Median = 5.0; Standard Deviation = 2.0
    b. Median = 4.5; Standard Deviation = 2.3
    c. Median = 5.0; Standard Deviation = 5.0
    d. Median = 4.5; Standard Deviation = 1.5

Q9. The portfolio expected return of two investments
    a. will be higher when the covariance is zero.
    b. will be higher when the covariance is negative.
    c. will be higher when the covariance is positive.
    d. does not depend on the covariance.

Q10. If two events are mutually exclusive and collectively exhaustive, what is the probability that one or the other occurs?
    a. 0.
    b. 0.50.
    c. 1.00.
    d. Cannot be determined from the information given.

Q11. Major league baseball salaries averaged $1.5 million with a standard deviation of $0.8 million in 1994. Suppose a sample of 100 major league players was taken. Find the approximate probability that the average salary of the 100 players exceeded $1 million.
    a. Approximately 0
    b. Approximately 0.257
    c. Approximately 0.736
    d. Approximately 1

Q12. A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence interval: (0.438, 0.642). Based on the interval above, is the population proportion of females equal to 0.60?
    a. No, and we are 90% sure of it.
    b. No. The proportion is 54.17%.
    c. Maybe. 0.60 is a believable value of the population proportion based on the information above.
    d. Yes, and we are 90% sure of it.

Q13. The probability that

house sales will increase in the next 6 months is estimated to be 0.25

the interest rates on housing loans will go up in the same period is estimated to be 0.74

house sales or interest rates will go up during the next 6 months is estimated to be 0.89

The probability that neither house sales nor interest rates will increase during the next 6 months is:
    a. 0.11
    b. 0.195
    c. 0.89
    d. 0.90

Q14. According to a survey of American households, the probability that the residents own 2 cars if annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that the residents of a household do not own 2 cars and have an income over $25,000 a year is:
    a. 0.12
    b. 0.18
    c. 0.22
    d. 0.48

Q15. A professor of economics at a small Texas university wanted to determine what year in school students were taking his tough economics course. Shown below is a pie chart of the results. What percentage of the class took the course prior to reaching their senior year?

    a. 14%
    b. 44%
    c. 54%
    d. 86%

Q16. Referring to the histogram, how many graduating seniors attended the luncheon?

    a. 4
    b. 152
    c. 275
    d. 388

Q17. Which of the following is true regarding the sampling distribution of the mean for a large sample size?
    a. It has the same shape, mean, and standard deviation as the population.
    b. It has a normal distribution with the same mean and standard deviation as the population.
    c. It has the same shape and mean as the population, but has a smaller standard deviation.
    d. It has a normal distribution with the same mean as the population but with a smaller standard deviation.

Q18. The width of each bar in a histogram corresponds to the:
    a. differences between the boundaries of the class.
    b. number of observations in each class.
    c. midpoint of each class.
    d. percentage of observations in each class.

Q19. A sample of 200 students at a Big-Ten university was taken after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorly on the midterm. The following table contains the result.
Did Well on Midterm Did Poorly on Midterm Studying for Exam 80 20 Went Bar Hopping 30 70
Referring to the table, of those who did well on the midterm in the sample, _______ percent of them went bar hopping the weekend before the midterm.
    a. 15
    b. 27.27
    c. 30
    d. 50

Q20. According to a survey of American households, the probability that the residents own 2 cars if annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that annual household income is over $25,000 if the residents of a household do not own 2 cars is:
    a. 0.12
    b. 0.18
    c. 0.40
    d. 0.55

Q21. Most analysts focus on the cost of tuition as the way to measure the cost of a college education. But incidentals, such as textbook costs, are rarely considered. A researcher at UMT wishes to estimate the textbook costs of first-year students at UMT. To do so, she monitored the textbook cost of 250 first-year students and found that their average textbook cost was $300 per semester. Identify the sample in the study.
    a. All Drummand University students.
    b. All college students.
    c. All first-year Drummand University students.
    d. The 250 students that were monitored.

Q22. Tim was planning for a meeting with his boss to discuss a raise in his annual salary. In preparation, he wanted to use the Consumer Price Index to determine the percentage increase in his salary in terms of real income over the last three years. Which method of data collection was involved when he used the Consumer Price Index?
    a. Published sources
    b. Experimentation
    c. Surveying
    d. Observation

Q23. If two equally likely events A and B are mutually exclusive and collectively exhaustive, what is the probability that event A occurs?
    a. 0
    b. 0.50
    c. 1.00
    d. Cannot be determined from the information given.

Q24. The collection and summarization of the socioeconomic and physical characteristics of the employees of a particular firm is an example of:
    a. inferential statistics.
    b. descriptive statistics.
    c. a parameter.
    d. a statistic.

Q25. The probability that

house sales will increase in the next 6 months is estimated to be 0.25.

the interest rates on housing loans will go up in the same period is estimated to be 0.74

house sales or interest rates will go up during the next 6 months is estimated to be 0.89

The probability that house sales will increase but interest rates will not during the next 6 months is:

    a. 0.065
    b. 0.15
    c. 0.51
    d. 0.89

Q26. The employees of a company were surveyed on questions regarding their educational background and marital status. Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is single or has a college degree is:
    a. 0.10
    b. 0.25
    c. 0.667
    d. 0.733

Q27. Since a _______ is not a randomly selected probability sample, there is no way to know how well it represents the overall population.
    a. simple random sample
    b. quota sample
    c. stratified sample
    d. cluster sample

Q28. Which of the mean, median, mode, and geometric mean are resistant measures of central tendency?
    a. The mean and median.
    b. The median and mode.
    c. The mode and geometric mean.
    d. The mean and mode.

Q29. A lab orders 100 rats a week for each of the 52 weeks in the year for experiments that the lab conducts. Suppose the mean cost of rats used in lab experiments turned out to be $13.00 per week. Interpret this value.
    a. Most of the weeks resulted in rat costs of $13.00.
    b. The median cost for the distribution of rat costs is $13.00.
    c. The expected or average cost for all weekly rat purchases is $13.00.
    d. The rat cost that occurs more often than any other is $13.00.

Q30. A lab orders 100 rats a week for each of the 52 weeks in the year for experiments that the lab conducts. Prices for 100 rats follow the following distribution:
Price: $10.00 $12.50 $15.00 Probability: 0.35 0.40 0.25
How much should the lab budget for next year's rat orders be, assuming this distribution does not change?
    a. $520
    b. $637
    c. $650
    d. $780

Q31. The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.
Time (in Minutes) Relative Frequency 0 but less than 5 0.37 5 but less than 10 0.22 10 but less than 15 0.15 15 but less than 20 0.10 20 but less than 25 0.07 25 but less than 30 0.07 30 or more 0.02
Referring to the table, what is the width of each class?
    a. 1 minute
    b. 5 minutes
    c. 2%
    d. 100%

Q32. A population frame for a survey contains a listing of 72,345 names. Using a table of random numbers, how many digits will the code numbers for each member of your population contain?
    a. 3
    b. 4
    c. 5
    d. 6

Q33. Which of the following is not true about the Student's t distribution?
    a. It has more area in the tails and less in the center than does the normal distribution.
    b. It is used to construct confidence intervals for the population mean when the population standard deviation is known.
    c. It is bell shaped and symmetrical.
    d. As the number of degrees of freedom increases, the t distribution approaches the normal distribution.

Q34. If you were constructing a 99% confidence interval of the population mean based on a sample of n = 25 where the standard deviation of the sample s = 0.05, the critical value of t will be:
    a. 2.7969
    b. 2.7874
    c. 2.4922
    d. 2.4851

Q35. A recent survey of banks revealed the following distribution for the interest rate being charged on a home loan (based on a 30-year mortgage with a 10% down payment).
Interest Rate: 7.0% 7.5% 8.0% 8.5% 8.5% Probability 0.12 0.23 0.24 0.35 0.06
If a bank is selected at random from this distribution, what is the chance that the interest rate charged on a home loan will exceed 8.0%?
    a. 0.06
    b. 0.41
    c. 0.59
    d. 1.00

Q36. The head librarian at the Library of Congress has asked her assistant for an interval estimate of the mean number of books checked out each day. The assistant provides the following interval estimate: from 740 to 920 books per day.

If the head librarian knows that the population standard deviation is 150 books checked out per day, and she asked her assistant to use 25 days of data to construct the interval estimate, what confidence level can she attach to the interval estimate?
    a. 99.7%
    b. 99.0%
    c. 98.0%
    d. 95.4%

Q37. Why is the Central Limit Theorem so important to the study of sampling distributions?
    a. It allows us to disregard the size of the sample selected when the population is not normal.
    b. It allows us to disregard the shape of the sampling distribution when the size of the population is large.
    c. It allows us to disregard the size of the population we are sampling from.
    d. It allows us to disregard the shape of the population when n is large.

Q38. Which of the following is most likely a parameter as opposed to a statistic?
    a. The average score of the first five students completing an assignment.
    b. The proportion of females registered to vote in a county.
    c. The average height of people randomly selected from a database.
    d. The proportion of trucks stopped yesterday that were cited for bad brakes.

Q39. Selection of raffle tickets from a large bowl is an example of:
    a. sampling with replacement.
    b. sampling without replacement.
    c. subjective probability.
    d. None of the above.

Q40. In left-skewed distributions, which of the following is the correct statement?
    a. The distance from Q1 to Q2 is smaller than the distance from Q2 to Q3.
    b. The distance from the smallest observation to Q1 is larger than the distance from Q3 to the largest observation.
    c. The distance from the smallest observation to Q2 is smaller than the distance from Q2 to the largest observation.
    d. The distance from Q1 to Q3 is twice the distance from Q1 to Q2.

Explanation / Answer

Ans;

1.b) The 25,000 adult American pine trees in the forest.

2.c) interquartile range and median.

3.b) a Sample Space

4.d) Cannot be determined from the information given.

5.c) for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population

6.d) descriptive statistics.

7. a) 0.86466

9.c) will be higher when the covariance is positive.

10. a) 0.

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