Deck 4: Sampling and Estimation

Question 1

What could cause a sample mean to be a poor point estimate of the population mean?

A)a small sample including several values at the high end of the population range
B)a small,homogeneous sample from the population
C)the sample standard deviation is large
D)the sample standard deviation is small

Answer 1

a small sample including several values at the high end of the population range

Question 2

A major consumer products company wants to measure the quality of the packaging of their products on the store shelves.Five large cities are chosen in different parts of the country.What sampling method is being used for this sampling plan?

A)simple random sampling
B)continuous sampling
C)subjective sampling
D)stratified sampling

Answer 2

stratified sampling

Question 3

Sampling from a continuous process ________.

A)does not involve a trade-off between cost and information obtained
B)should be used only as a last resort as it requires a large amount of resources
C)introduces two types of sampling error called α and β
D)can be accomplished by selecting a random time for n items to be collected

Answer 3

can be accomplished by selecting a random time for n items to be collected

Question 4

Stratified random sampling ________.

A)eliminates homogeneous sampling error
B)is used with populations that are naturally divided into subsets
C)has the drawback of introducing sampling bias
D)allocates sampling error disproportionately

Question 5

Which of the following errors can be made while attempting to obtain statistics that measure population parameters?

A)minimal error and maximal error
B)cost error and informative error
C)sample error and population error
D)nonsampling error and sampling error

Question 6

A major consumer products company wants to measure the quality of the packaging of their products on the store shelves.In a chain grocery store,all of the packages of a 15-ounce Wild Berry shampoo and all of the packages of a 4-ounce Man-O-Manly deodorant are sampled.What sampling method is being used for this sampling plan?

A)cluster sampling
B)simple random sampling
C)continuous sampling
D)protracted random sampling

Question 7

Cluster sampling ________.

A)is used with populations that are naturally divided into subsets
B)requires difficult sorting of the population data into specific samples
C)consists of a census of selected population subgroups
D)ensures each individual item has an equal chance of selection

Question 8

The importance of sampling,from a managerial perspective,is to ________.

A)obtain information to draw a valid inference about a population
B)calculate the population parameters accurately
C)test the correlation between the values of the population
D)find all the defective products in the population

Question 9

Systematic sampling ________.

A)is the same as simple random sampling
B)ensures each item has an equal chance of selection
C)is difficult to use because a machine is required to select each sample
D)selects items periodically from the population

Question 10

All of the following are true about the sampling distribution of the mean except ________.

A)the population standard deviation can be determined when a large sample size is used
B)the standard deviation of this distribution is called the standard error of the mean
C)when larger sample sizes are used for this distribution,the sampling error is less
D)this distribution approaches the normal distribution if the sample size is large enough

Question 11

In simple random sampling ________.

A)every subset has an equal chance of being selected
B)sampling is taken from the most easily available segments of the population
C)every n^th item is selected from the population
D)weights are assigned to each value based on the probability that it will be included in the sample

Question 12

A sampling plan should contain all of the following except ________.

A)the objectives of the sample activity
B)the standards for sample quality
C)the target population and population frame
D)the method of sampling including operational procedures for sample collecting

Question 13

A major consumer products company wants to measure the type and quantity of laundry detergent used by consumers.After choosing a suburban street at random,employees go door-to-door to every fifth house to ask for permission to view their laundry detergent supply.What sampling method is being used for this sampling plan?

A)simple random sampling
B)systematic sampling
C)continuous sampling
D)subjective sampling

Question 14

In designing a sampling plan,the population frame is ________.

A)the objectives of the sampling activity
B)the target population
C)the list from which the sample is selected
D)the sampling procedures

Question 15

A random number is a number that ________.

A)is selected through subjective sampling
B)can only be found in a random number table
C)is precise to six decimal places
D)is uniformly distributed between 0 and 1

Question 16

All of the following are reasons why random sampling is important for statistical applications except ________.

A)the outcomes are more readily understood and therefore really usable
B)solving using mathematics alone may be very difficult if not impossible
C)the outcome variables are complicated functions of several input random variables
D)sampling experiments can be used to better understand important statistics theories

Question 17

Which of the following is a subjective sampling method?

A)cluster sampling
B)judgment sampling
C)systematic sampling
D)stratified sampling

Question 18

The sampling distribution of the mean is ________.

A)always symmetrical
B)a distribution of the probabilities of estimating the population mean accurately through sampling
C)the distribution of all the values in the sample
D)the distribution of the means of all possible samples of a fixed sample size n from some population

Question 19

A sampling plan ________.

A)states the design quality for production managers
B)describes the characteristics of a population
C)is used when the product or process is not well understood
D)describes the approach that will be used to obtain samples from a population

Question 20

The basic difference between subjective and probabilistic sampling methods is whether ________.

A)the data collected is qualitative or quantitative
B)a random procedure is used or not
C)a person or object is being sampled
D)actual measurements are being taken or estimates are being used

Question 21

Peak Previously Played Picks buys and sells used sports equipment.For the past year,the mean purchase of used sports equipment was $36 with a standard deviation of $8.Find the probability that the mean purchase from a sample of 16 customers will be less than $20.Use the Microsoft Excel function NORM.DIST.

A)0.00%
B)100.0%
C)2.28%
D)69.13%

Question 22

A point estimate ________.

A)has a known measurement error
B)can be found by dividing the population parameter by the sample size
C)accurately estimates the population parameter
D)is a sample-based estimate of a population parameter

Question 23

The central limit theorem states that if the sample size is large enough,________.

A)the sampling distribution of the mean is normally distributed only if the population is also normally distributed
B)the mean of the sampling distribution will be the same as that of the population
C)the sample mean deviates from the population mean except when the population itself is uniformly distributed
D)the sample mean will exceed the population mean

Question 24

Peak Previously Played Picks buys and sells used sports equipment.For the past year,the mean purchase of used sports equipment was $36 with a standard deviation of $8.Using the Microsoft Excel function NORM.DIST,find the probability that the next person who comes in to sell used equipment will be paid less than $20.

A)2.28%
B)69.15%
C)100.00%
D)97.73%

Question 25

What sample size would be required to translate a population standard deviation from 2.9 to a standard error of the mean that is of the standard deviation?

A)100
B)10
C)0.841
D)1000

Question 26

Find the standard error of the mean when the population standard deviation is 4.1 and a sample of size 30 is taken.

A)7.32
B)0.08
C)1.34
D)0.75

Question 27

Given that σ is the standard deviation of the population,n is the sample size,and is the population mean,the standard error of the mean is calculated by ________.

A)σ
B)
C)
D)

Question 28

The central limit theorem states that no matter what the underlying population,the distribution of the sample means is ________.

A)approximately normally distributed
B)broadly symmetrical
C)bimodal
D)unpredictable

Question 29

Peak Previously Played Picks buys and sells used sports equipment.For the past year,the mean purchase of used sports equipment was $36 with a standard deviation of $8.Using the Microsoft Excel function NORM.DIST,find the probability that the next person who comes in to buy used equipment will pay more than $40.

A)30.85%
B)69.15%
C)24.20%
D)95.60%

Question 30

Find the standard error of the mean when the population standard deviation is 0.7 and a sample of size 50 is taken.

A)0.099
B)0.014
C)0.028
D)7.14

Question 31

Regarding the standard error of the mean,________.

A)as the sample size increases,the standard error increases
B)as the sample size decreases,the standard error decreases
C)as the sample size increases,the standard error decreases
D)it is defined as one-half of the population standard deviation

Question 32

Peak Previously Played Picks buys and sells used sports equipment.For the past year,the mean purchase of used sports equipment was $36 with a standard deviation of $8.Find the probability that the mean purchase from a sample of 16 customers will be greater than $40.Use the Microsoft Excel function NORM.DIST.

A)2.28%
B)69.15%
C)100.00%
D)97.73%

Question 33

Find the standard error of the mean when the population standard deviation is 2.4 and a sample of size 36 is taken.

A)4.03
B)0.6
C)14.4
D)0.4

Question 34

Peak Previously Played Picks buys and sells used sports equipment.For the past year,the mean purchase of used sports equipment was $36 with a standard deviation of $8.Using the Microsoft Excel function NORM.DIST,find the probability that the next person who comes in to sell used equipment will be paid between $20 and $40.

A)66.87%
B)71.42%
C)33.13%
D)28.58%

Question 35

The standard error of the mean is ________.

A)the variance of the sampling distribution of the mean
B)the standard deviation of the sampling distribution of the mean
C)the range of the sampling distribution of the mean
D)the mean of the sampling distribution of the standard deviations

Question 36

Which of the following distributions is most likely to approach a normal distribution?

A)distribution of all possible sample means of sample size 90
B)distribution of all possible sample means of sample size 60
C)distribution of all possible sample means of sample size 120
D)distribution of all possible sample means of sample size 30

Question 37

Find the standard error of the mean when the population standard deviation is 14.1 and a sample of size 33 is taken.

A)8.79
B)0.43
C)2.34
D)2.45

Question 38

Find the standard error of the mean when the population standard deviation is 160 and a sample of size 16 is taken.

A)0.14
B)40
C)1.26
D)10

Question 39

A point estimate is used ________.

A)because it's easier to use all the values in the data set than a single value
B)to estimate the value of a population estimate
C)when the population parameter is known
D)only when the population proportion is not known

Question 40

The two most commonly used types of estimates in statistics are ________.

A)cluster intervals and standard estimates
B)unbiased estimator and standard distribution
C)point estimates and confidence intervals
D)sampling estimates and central limit interval

Question 41

Confidence interval estimates of a population parameter ________.

A)provide a range of values within which the true value of the parameter is believed to be
B)specify a value that accurately predicts the population parameter
C)eliminates the effect of sampling error
D)are used solely to estimate the value of population variance

Question 42

Statisticians have determined that in order for the calculation of sample variance to result in an unbiased estimate,the denominator in the formula must be ________.

A)n - 1
B)n
C)n
D)n + 1

Question 43

The basic difference between a point estimate and a confidence interval is ________.

A)a point estimate is used to estimate a sample statistic while a confidence interval is used to determine a population parameter
B)confidence intervals are statistically more certain than point estimates
C)a point estimate combines sampling error in a single value while a confidence interval is a range of value estimates
D)a point estimate is a single value while a confidence interval is a range of values

Question 44

An example of a confidence interval is ________.

A)A Wall Street Journal poll reports that 45% - 48% of farmers produce grains
B)A New York Times survey states that more than 65% of American families own their own homes
C)A Gallup poll reports that 56% ± 3% of voters support candidate A
D)An editorial in Smart Money magazine states that the President is confident he will be re-elected

Question 45

The α used to calculate a confidence interval can be understood as ________.

A)the probability that the population mean will not fall in the confidence interval
B)the difference between the population parameter and the sample statistic
C)the confidence that the population mean is known
D)the likelihood that the population mean was properly calculated

Question 46

The finite population correction factor (FPC)is found by ________.

A)
B)
C)
D)

Question 47

The margin of error used in a confidence interval is found by ________.

A)multiplying the standard error and z_α/2
B)multiplying the population standard deviation and the sample size
C)dividing the population standard deviation by the sample size
D)multiplying the level of confidence and the standard error

Question 48

A confidence interval using the known population standard deviation ________.

A)is the same as the point estimate for the population standard deviation
B)has the least sampling error compared to confidence intervals for mean
C)is the simplest type of confidence interval
D)uses only the 95% level of confidence

Question 49

For a 95% confidence interval for a population mean,there is ________.

A)a 95% confidence that the center of the interval is the true population mean
B)a 95% probability that the true population mean will fall in that range of values
C)a 95% probability that the population mean comes from a normal distribution
D)a 95% confidence that the sample mean is the true population mean

Question 50

A sample mean of 4.56 ounces was just measured from a population of which the population mean is not known.What value should be used for the population mean?

A)2.125 ounces
B)none,since the population mean cannot be estimated
C)4.56 ounces
D)the average of all the sample means

Question 51

Given that a sample of size 32 and a population standard deviation of 0.3,what would be the margin of error at a 90% level of confidence?

A)±0.9186
B)±1.018
C)±0.4452
D)±0.09

Question 52

From a sample of 25 items,a sample standard deviation of 4.56 ounces was just measured.What value should be used for the population standard deviation?

A)0.91 ounces
B)4.56 ounces
C)none,since the population standard deviation cannot be estimated
D)0.18 ounces

Question 53

Given that a sample of size 12 and population standard deviation of 1.8,what would be the margin of error at a 95% level of confidence?

A)±1.018
B)±0.9186
C)±12.22
D)±0.4452

Question 54

When using 95% confidence intervals for a population mean ________.

A)from 100 sample-based intervals,there would be 95 different sample means
B)95% of any number of sample-based intervals will contain the population mean
C)not more than 5% of the confidence intervals should be sampled
D)of 100 sample-based intervals,95 would contain the true population mean

Question 55

Given that a sample of size 60 and a population standard deviation of 1.3,what would be the margin of error at a 95% level of confidence?

A)±0.01
B)±3.29
C)±0.33
D)±0.4452

Question 56

A finite population correction factor should be used to adjust the margin of error when the sample taken is larger than ________ of the entire population.

A)10%
B)1%
C)5%
D)50%

Question 57

The finite population correction (FPC)factor is used to improve the standard error by ________.

A)dividing the standard error by the FPC
B)multiplying the standard error and the FPC
C)adding the FPC to the standard error
D)subtracting the FPC from the standard error

Question 58

The t‐distribution converges to the standard normal distribution ________.

A)as the number of degrees of freedom increases
B)as the sample mean increases
C)as the population size increases
D)as the variance falls

Question 59

An estimator is said to be unbiased if ________.

A)its expected value equals the population parameter
B)it is greater than one
C)it is estimated from a relatively small sample
D)it is equal to or lesser than zero

Question 60

A sample was taken of computation errors on an exam: 4,7,3,8,4,4,6,1,5,2,4,8,5,4,5.What value should be used for the population standard deviation?

A)0.51
B)1.99
C)none,since the population standard deviation should never be estimated
D)1.92

Question 61

Use the Microsoft Excel function CONFIDENCE.NORM to find the confidence interval for a population mean of $19 at a 95% level of confidence with a sample size of 12 and standard deviation of $1.8.

A)$17.98 to $20.02
B)$18.97 to $19.03
C)-$4.52 to $42.52
D)$17.20 to $20.80

Question 62

The unbiased estimator of population proportion where there are only two possible outcomes is the ________.

A)sample proportion
B)sample mean
C)sample percentage
D)sample size

Question 63

Given that a sample of size 32 was taken from a finite population of 90 with a population standard deviation of 1.8,what would be the margin of error at a 95% level of confidence?

A)±0.237
B)±1.262
C)±0.4452
D)±0.822

Question 64

The t-distribution is very much like the standard normal distribution except that the t-distribution ________.

A)has a smaller variance
B)has a smaller standard deviation
C)is bi-symmetrical
D)has a larger variance

Question 65

What is the value of the finite population correction factor when a sample size of 250 is taken from a finite population of 1001?

A)0.7510
B)0.8667
C)1.9960
D)0.2498

Question 66

As the level of confidence decreases,________.

A)the confidence interval becomes wider
B)the confidence interval is unchanged
C)the confidence interval becomes irrelevant
D)the confidence interval becomes more narrow

Question 67

Find the confidence interval for a population mean of 1.6 pounds at a 95% level of confidence with a sample size of 112 and standard deviation of 0.2 pounds.

A)1.89 to 1.90 pounds
B)4.52 to 42.52 pounds
C)1.56 to 1.64 pounds
D)1.72 to 2.08 pounds

Question 68

As the sample size increases,________.

A)the confidence interval becomes more narrow
B)the confidence interval becomes wider
C)the confidence interval is unchanged
D)the confidence interval becomes irrelevant

Question 69

The risk that the confidence interval does not contain the population mean can be reduced by ________.

A)decreasing the sample size
B)increasing the population size
C)increasing the sample size
D)decreasing the population size

Question 70

As the confidence interval becomes wider,the likelihood that the population mean ________.

A)will be contained in that interval decreases
B)will be in that interval is unchanged
C)will be contained in that interval increases
D)will be in the interval becomes irrelevant

Question 71

The degrees of freedom correspond to ________.

A)the number of sample values that are inaccurate
B)the number of population values accurately estimated by the sample values
C)the number of sample values that are free to vary
D)the explicit estimate of the variance

Question 72

Given that a sample of size 12 was taken from a finite population of 60 with a population standard deviation of 1.8,what would be the margin of error at a 95% level of confidence?

A)±1.018
B)±0.9186
C)±12.22
D)±0.4452

Question 73

Different t-distributions are determined by ________.

A)the height of the distribution
B)the number of peaks
C)different degrees of freedom
D)different populations

Question 74

For a sample size of 172,the degrees of freedom are ________.

A)172
B)171
C)13.11
D)173

Question 75

There is virtually no difference between t-values and their corresponding z-values when the sample size is greater than ________.

A)1000
B)100
C)30
D)12

Question 76

For a sample size of 12,the degrees of freedom are ________.

A)13
B)144
C)11
D)3.46

Question 77

What is the value of the finite population correction factor when a sample size of 25 was taken from a finite population of 101?

A)0.87
B)0.76
C)0.36
D)1.32

Question 78

Find the confidence interval for a population mean of 615 acres at a 90% level of confidence with a sample size of 52 and standard deviation of 27 acres.

A)189 to 1190 acres
B)608.84 to 621.16 acres
C)452 to 4252 acres
D)172 to 2008 acres

Question 79

What is the value of the finite population correction factor when a sample size of 125 was taken from a finite population of 500?

A)0.75
B)1.15
C)0.87
D)1.33

Question 80

Occasionally,a confidence interval for population variability may be desired.In this case,the confidence interval could be found for the ________.

A)mean
B)median
C)standard deviation
D)proportion