BA6933 Ch-06

1.The binomial probability distribution is most symmetric when _____.A) p equals 0.5

2.The key difference between binomial and hypergeometric distributions is that with the hypergeometric distribution the _____. A) probability of success changes from trial to trial

3.In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the _____. A) Poisson distribution

4.The expected value of a random variable is the _____. A) mean value

5.A description of how the probabilities are distributed over the values the random variable can assume is called a(n) _____. A description of how the probabilities are distributed over the values the random variable can assume is called a(n) _____. A) probability distribution

6.A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a _____. A) binomial probability distribution

7.Which of the following is NOT a characteristic of an experiment where the binomial probability distribution is applicable? A) The trials are dependent.

8.To compute a binomial probability. we must know all of the following except the _____. A) number of elements in the population

9.The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The random variable in this problem is ________________________________________. A) the number of days out of 3 that Pete catches fish

10.If one wanted to find the probability of 10 customer arrivals in an hour at a service station, one would generally use the _____. A) Poisson probability distribution

11.The monthly number of applications for admission to UD is a discrete random variable. A) True

12.Highway patrol officers measure the speed of automobiles on a highway using radar equipment. The random variable in this experiment is speed, measured in miles per hour. This random variable is a discrete random variable. A) False

13.The Poisson random variable is an example of a continuous random variable. A) False

14.The binomial probability distribution is appropriate to use for “without replacement” type problems. A) False

15.Posterior probabilities are computed using _____ A) Bayes’ theorem

16.After the data have been arranged from smallest value to largest value, the value in the middle is called the _____. A) median

17.The interquartile range is used as a measure of variability to overcome what difficulty of the range? A) The range is influenced too much by extreme values.

18.A graphical summary of data that is based on a five-number summary is a _____. A) boxplot

19.The coefficient of variation indicates how large the standard deviation is relative to the _____. A) Mean

20.Which of the following symbols represents the standard deviation of a population? A) σ

21.An important numerical measure related to the shape of a distribution is the _____. A) skewness

22.A proficiency exam was given to employees of a firm. Seventy percent of the firm’s employees passed the exam. The probability that an employee was female and passed the examination was 0.56.
If a randomly selected employee passed the exam, what is the probability that the employee is a female?
A) 0.80

23.A proficiency exam was given to employees of a firm. 60% of the firm’s employees passed the exam. 30% of the employees are male. The probability that an employee was female and passed the examination was 0.56.
What is the probability that a randomly selected employee is female or passed the exam?
A) 0.74

24.If A and B are independent events with P(A) = .2 and P(B) = .6, then P(A ∪ B) = _____. A) 0.68

25.On a December day, the probability of snow is .30. The probability of a “cold” day is .50. The probability of snow and a “cold” day is .15. Thus, snow and “cold” weather are _____. A) independent events

26.If P(A) = .62, P(B) = .56, and P(A ∪ B) = .70, then P(B | A) = _____. A) 0.7742

27.Events A and B are mutually exclusive. Which of the following statements is also true? A) P(A ∪ B) = P(A) + P(B)

28.he _____ denotes the number of standard deviations xi is from the mean . A) z-score

29.The symbol for the sample variance is s2. A) True

30.The Empirical Rule can only be applied if the data distribution is bell-shaped. A) True

31.The median is used in creating a boxplot. A) True

32.In combinations, the order of selection is important. A) False

33.The mean is a better measure of center than the median if there is an outlier in the data set. A) False

34.The correlation coefficient can never be negative. A) False

35.Excel’s __________ can be used to construct a crosstabulation. A) Pivot Table tool

36.Which of the following would likely display a negative relationship when creating a scatter diagram? A) The number of classes a student misses during a semester and the grade obtained in the course

37.A company wants to enhance the benefits for its yearly healthcare package offering. It observes the set of employees who smoke on their break times at 10 a.m., 12 p.m., and 2 p.m. It records the number of cigarettes smoked by each individual. This is an example of: A) an observational study

38.The summaries of data, which may be tabular, graphical, or numerical, are referred to as: A) descriptive statistics.

39.All of the following are examples of observational studies except: A) the behavior of Walmart shoppers after they are given a $20 gift card from the store.

40.The number of observations in a complete data set having 20 elements and 3 variables is: A) 20

41.A set of visual displays that organizes and presents information that is used to monitor the performance of a company or organization in a manner that is easy to read, understand, and interpret is called a: A) data dashboard.

42.Examples of categorical data include allof the following except: A)  90210 (Beverly Hills).

43.In a post office, the mailboxes are numbered from 1 to 5,000. These numbers represent A) categorical data

44.Taking repeated samples until you obtain the desired result is not an ethically acceptable statistical practice. A) True

45.In a crosstabulation, both variables must be quantitative. A) False

46.A histogram is appropriate to be used for categorical data. A) False

47.A pie chart is appropriate for categorical data. A) True

48.A prediction made from sample data is an example of an inferential statistic. A) True

49.Numerical calculations are always appropriate for nominal data. A) False

50.The ages of students at a university are normally distributed with a mean of 21. What percentage of the student body is at least 21 years old? A) 50%

51.What type of function defines the probability distribution of ANY continuous random variable? A) Probability density function

52.Which of the following is NOT a characteristic of the normal probability distribution? A) The graph of the curve is the shape of a rectangle.

53.Exponential distributions _____. A) are not skewed

54.Which of the following is NOT a characteristic of the normal probability distribution? A) The standard deviation must be 1.

55.The weight of items produced by a machine is normally distributed with a mean of 8 ounces and a standard deviation of 2 ounces. What is the random variable in this experiment? A) Weight of items produced by a machine

56.A continuous probability distribution that is useful in describing the time, or space, between occurrences of an event is a(n) _____probability distribution. A) exponential

57.The weight of items produced by a machine is normally distributed with a mean of 8 ounces and a standard deviation of 2 ounces. What is the probability that a randomly selected item weighs exactly 8 ounces? A) 0

58.The assembly time for a product is uniformly distributed between 6 and 10 minutes. The probability of assembling the product in less than 6 minutes is _____. A) 0

59.For a uniform probability density function, the height of the function _____. A)  is the same for each value of x

60.The exponential distribution is a discrete probability distribution. A) False

61.the variable Z represents a standard normal random variable. A) True

62.If the random variable X = number of occurrences has a Poisson distribution, then the random variable Y = time between occurrences has an exponential distribution. A) True

63.The mean of a standard normal random variable is one. A) False

64.The level of significance α (alpha) is the probability that the confidence interval does not contain the value of the parameter being estimated. A) True

65.The Central Limit Theorem can only be used when the population being sampled is normally distributed. A) False

66.Cluster sampling is a probability-based sampling method. A) True

67.The RAND() function in Excel can be used to find a probability. A) False

68.An interval estimate provides a single value estimate for a population parameter. A) False

69.Every confidence interval constructed will contain the value of the parameter being estimated. A) False

70.The sample mean provides a point estimate for the population mean. A) True

71.The margin of error in an interval estimate of the population mean is a function of all of the following EXCEPT _____. A)  sample mean

72.Which of the following is NOT a probability-based sampling method? A) Volunteer Sampling

73.When the population has a normal distribution, the sampling distribution of x-bar is normally distributed _____. A) for any sample size

74.A single numerical value used as an estimate of a population parameter is known as a _____. A) point estimate

75.The general form of an interval estimate of a population mean or population proportion is the _____ plus or minus the _____. A) point estimate, margin of error

76.The t distribution is a family of similar probability distributions, with each individual distribution depending on a parameter known as the _____. A) degrees of freedom

77.The use of the normal probability distribution as an approximation of the sampling distribution of is based on the condition that both np and n (1 – p) equal or exceed _____. A) 5

78.If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the _____. A) width of the confidence interval to increase

79.Whenever the population standard deviation is unknown, which distribution is used in developing an interval estimate for a population mean? A) t distribution

80.The standard deviation of all possible x-bar values is called the _____. A) standard error of the mean

81.Which of the following is a point estimator? A) S

82.The fact that the sampling distribution of the sample mean can be approximated by a normal probability distribution whenever the sample size is large is based on the _____. A) Central Limit Theorem

83.This sampling method involves breaking the population up into subgroups and taking a simple random sample from each of the subgroups. A) Stratified Random Sampling

84.All of the following are true about the standard error of the mean EXCEPT _____. A) it is larger than the standard deviation of the population

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