Stats

A quantitative variable is the only type of variable that can: A)assume numeric values for which arithmetic operations make sense B)be graphed C)be used to prepare tables D)have no intermediate values

A) Assume numeric values for which arithmetic operations make sense

Which of the following is not a condition of the binomial experiment? A) There are only two trials B) Each trial has two and only two outcomes C) p is the probability of success, q is the probability of failure, and D) The trials are independent

A) There are only two trials

We obtain the relative frequency of a category by: A) dividing the frequency of that category by the sum of all frequencies B) multiplying the frequency of that category by 100 C) dividing the frequency of that category by 100 D) dividing the sum of all frequencies by the frequency of that category

A) dividing the frequency of that category by the sum of all frequencies

In a frequency histogram, the frequency of a class is the: A) height of the corresponding bar B) width of the corresponding bar C) height multiplied by the width of the corresponding bar D) height divided by the width of the corresponding bar

A) height of the corresponding bar

An outlier influences which of the following summary measures the most? A) mean B) median C) mode D) median and mode

A) mean

23. According to the Central Limit Theorem, the sampling distribution of the sample mean is approximately normal, irrespective of the shape of the population distribution, if: A) n is 30 or larger B) n is less than 30 C) np and nq are both greater than 5 D) n is 50 or larger

A) n is 30 or larger

43. Estimation is a procedure by which we assign a numerical value or numerical values to the: A) population parameter based on the information collected from a sample B) sample statistic based on the information collected from a sample C) population parameter based on the information collected from a population D) sample statistic based on the information collected from a population

A) population parameter based on the information collected from a sample

35. The z value for a 99% confidence interval for the population mean with known is: A) 2.05 B) 2.58 C) 2.17 D) 1.60

B) 2.58

According to the empirical rule, the percentage of values that fall within two standard deviations of the mean is approximately: A) 93% B) 95% C) 94% D) 91%

B) 95%

According to the empirical rule, the percentage of values that fall within three standard deviations of the mean is approximately: A) 99.4% B) 99.7% C) 97.9% D) 97.3%

B) 99.7%

Which of the following pairs of events are mutually exclusive? A) Female and democrat B) Female and male C) Female and republican D) Democrat and no opinion E) Male and republican F) Male and no opinion

B) Female and male D) Democrat and no opinion

The normal probability distribution is applied to: A) a discrete random variable B) a continuous random variable C) any random variable D) a subjective random variable

B) a continuous random variable

A discrete variable is a variable that can assume: A) categorical values only B) a countable set of values only C) an uncountable set of values D) non-numerical values

B) a countable set of values only

If the population from which samples are drawn is not normally distributed, then the sampling distribution of the sample mean is: A) never normally distributed B) approximately normally distributed if n is 30 or larger C) always normally distributed D) approximately normally distributed if n is less than 30

B) approximately normally distributed if n is 30 or larger

We obtain the percentage of a category by: A) multiplying the frequency of that category by 100 B) multiplying the relative frequency of that category by 100 C) dividing the frequency of that category by 100 D) dividing the sum of all frequencies by the frequency of that category

B) multiplying the relative frequency of that category by 100

The tails of a normal distribution curve: A) meet the horizontal axis at z = 3.0 B) never meet or cross the horizontal axis C) cross the horizontal axis at z = 4.0 D) are nonsymmetric

B) never meet or cross the horizontal axis

24. A continuous random variable x has a normal distribution with a mean of 90 and a standard deviation of 15. The sampling distribution of the sample mean for a sample of 16 elements taken from this population is: A) not normal B) normal C) skewed to the right D) skewed to the left

B) normal

The mean of a binomial distribution is equal to: A) npq B) np C) square of npq D) square root of npq

B) np

14. The population distribution is the probability distribution of the: A) whole population of a country B) population data C) population means D) population probabilities

B) population data

A discrete random variable is a random variable: A) that can assume any value in one or more intervals B) whose set of values is countable C) that is derived from a random population D) that is determined by random probability

B) whose set of values is countable

36. The z value for a 85% confidence interval for the population mean with known is: A) 1.96 B) 2.33 C) 1.44 D) 2.58

C) 1.44

According to the empirical rule, the percentage of values that fall within one standard deviation of the mean is approximately: A) 63% B) 72% C) 68% D) 59%

C) 68%

Which of the following is an example of a discrete random variable? A) The weight of a box of cookies B) The length of a window frame C) The number of horses owned by a farmer D) The distance from home to work for a worker

C) The number of horses owned by a farmer

36. Which of the following is not a characteristic of the normal distribution? A) The total area under the curve is 1.0 B) The curve is symmetric about the mean C) The value of the mean is always greater than the value of the standard deviation D) The two tails of the curve extend indefinitely

C) The value of the mean is always greater than the value of the standard deviation

In statistics, a population consists of: A) all people living in a country B) all people living in the area under study C) all subjects or objects whose characteristics are being studied D) a selection of a limited number of elements

C) all subjects or objects whose characteristics are being studied

For a discrete random variable x, the probability of any value of x is: A) always greater than 1 B) always less than zero C) always in the range zero to 1 D) never greater than zero

C) always in the range zero to 1

21. If the population from which samples are drawn is normally distributed, then the sampling distribution of the sample mean is: A) not normally distributed B) normally distributed if n is 30 or larger C) always normally distributed D) normally distributed if n is less than 30

C) always normally distributed

A continuous variable is a variable that can assume: A) categorical values only B) a countable set of values only C) an uncountable set of values D) non-numerical values

C) an uncountable set of values

The probability of an event is always A) greater than zero B) less than 1 C) between 0 and 1, inclusive D) greater than 1

C) between 0 and 1, inclusive

The total area under a normal distribution curve to the left of the mean is always: A) equal to 1 B) equal to zero C) equal to 0.5 D) greater than .5

C) equal to 0.5

For a continuous random variable x, the total area under the probability distribution curve of x is always: A) less than 1 B) greater than 1 C) equal to 1 D) between zero and 1

C) equal to 1

The probability that a continuous random variable x assumes a single value is always: A) less than 1 B) greater than zero C) equal to zero D) between zero and 1

C) equal to zero

46. For most distributions, we can use the normal distribution to make a confidence interval for a population mean provided that the population standard deviation is known and the sample size is: A) greater than 30 B) less than 25 C) greater than or equal to 30 D) greater than 100

C) greater than or equal to 30

A symmetric distribution curve: A) has a longer tail on the right side B) has a longer tail on the left side C) is identical on both sides of the mean D) is triangular in shape

C) is identical on both sides of the mean

Which of the following is the only measure that can be calculated for qualitative data? A) mean B) range C) mode D) median

C) mode

33. The single value of a sample statistic that we assign to the population parameter is a: A) single estimate B) unique estimate C) point estimate D) singular estimate

C) point estimate

The probability distribution of a sample statistic is the: A) frequency distribution of that statistic B) binomial distribution of that statistic C) sampling distribution of that statistic D) Poisson distribution of that statistic

C) sampling distribution of that statistic

25. A continuous random variable x has a right-skewed distribution with a mean of 45 and a standard deviation of 6. The sampling distribution of the sample mean for a sample of 25 elements taken from this population is: A) approximately normal B) normal C) skewed to the right D) skewed to the left

C) skewed to the right

In general, "n factorial" represents: A) the product of any n numbers B) the sum of all integers from n to 1 C) the product of all integers from n to 1 D) n-1

C) the product of all integers from n to 1

In binomial experiments, the outcome called a "success" is an outcome: A) that is always beneficial B) that is linked to success C) to which the question refers D) that is favorable

C) to which the question refers

The margin of error for the population mean, assuming is known, is: A) z multiplied by the population standard deviation B) z multiplied by t C) z multiplied by the standard deviation of the sample mean D) z multiplied by the sample mean

C) z multiplied by the standard deviation of the sample mean

For the standard normal distribution, the mean is: A) 1 and the standard deviation is zero B) 0.5 and the standard deviation is 0.5 C) zero and the standard deviation is 1 D) 1 and the standard deviation is 1

C) zero and the standard deviation is 1

The ages of all high school teachers in New York state have a bell-shaped distribution with a mean of 45 years and a standard deviation of 3 years. According to the empirical rule, the percentage of teachers in this state who are 36 to 54 years old is approximately: A) 99.4% B) 97.9% C) 98.3% D) 99.7%

D) 99.7%

Which of the following is not a binomial experiment? A) Rolling a die 25 times and observing for an even or odd number B) Randomly selecting 50 items from a production line and observing if they are good or defective C) Rolling a die 20 times and observing for a number that is less than or equal to 4 or greater than 4 D) Selecting 50 adults and observing if they are in favor of an issue, against it, or have no opinion

D) Selecting 50 adults and observing if they are in favor of an issue, against it, or have no opinion

Which of the following is not an example of a discrete random variable? A) The number of days it rains in a month in New York B) The number of stocks a person owns C) The number of persons allergic to penicillin D) The time spent by a physician with a patient

D) The time spent by a physician with a patient

A distribution curve that is right-skewed has: A) both tails of the same length B) a longer tail on the left side C) a shorter tail on the right side D) a longer tail on the right side

D) a longer tail on the right side

In statistics, we define a sample as: A) people living in one city only B) the target population C) all items under investigation D) a portion of the population

D) a portion of the population

In a frequency distribution, the classes should always: A) be overlapping B) have the same frequency C) have a width of 10 D) be non-overlapping

D) be non-overlapping

A qualitative variable is the only type of variable that: A) can assume numerical values B) cannot be graphed C) can assume an uncountable set of values D) cannot be measured numerically

D) cannot be measured numerically

For the probability distribution of a discrete random variable x, the sum of the probabilities of all values of x must be: A) equal to zero B) in the range zero to 1 C) equal to 0.5 D) equal to 1

D) equal to 1

For a continuous random variable x, the area under the probability distribution curve between any two points is always: A) greater than 1 B) less than zero C) equal to 1 D) in the range zero to 1

D) in the range zero to 1

For a normal distribution, the z value for an x value that is to the right of the mean is always: A) equal to zero B) negative C) greater than 1 D) positive

D) positive

The summary measure obtained by taking the difference between the minimum and maximum values in a data set is the: A) median B) standard deviation C) variance D) range

D) range

The sampling distribution is the probability distribution of a: A) sample B) sample with replacement C) sample without replacement D) sample statistic

D) sample statistic

26. A continuous random variable x has a left-skewed distribution with a mean of 130 and a standard deviation of 22. The sampling distribution of the sample mean for a sample of 16 elements taken from this population is: A) approximately normal B) normal C) skewed to the right D) skewed to the left

D) skewed to the left

The standard deviation of a binomial distribution is equal to: A) npq B) np C) square of npq D) square root of npq

D) square root of npq

The hypergeometric probability distribution can be used whenever: A) a sample is drawn at random with replacement B) successive trials are independent of each other C) the probability of two outcomes remains constant D) the population is finite and sampling occurs without replacement

D) the population is finite and sampling occurs without replacement

118 124 82 94 117 The mode of this data set is: A) 42 B) 82 C) 117 D) this data set does not have a unique mode

D) this data set does not have a unique mode