Chapter 7 assign.

When the finite population correction factor is applied to the sample mean, the resulting standard error for the sample mean is equal to

(σ/√n)√(N−n)/(N−1).

________ is caused by a number of randomly occurring events that are part of the production process.

Chance variation

The purpose of statistical quality control is to

maintain high-quality goods and services.

Control charts were created to

monitor the behavior of a production process.

We can use the finite population correction factor when

n ≥ 0.05N.

If the shape of the population from which a simple random sample is drawn is normal, then the shape of the sampling distribution of X is

normal.

The probability distribution of the sample mean is commonly referred to as the _____.

sampling distribution of x

If we were to sample repeatedly from a given population, the average value of the sample means will equal

the population mean.

Bias can occur in sampling. Bias refers to

the tendency of a sample statistic to systematically over- or under-estimate a population parameter.

Which of the following is an example of a sample statistic?

x

In any production process, variation in the quality of the end product is inevitable. Chance variation, or common variation, refers to

A number of randomly occurring events that are part of the production process.

Which of the following statements is MOST accurate?

A parameter is a constant although its value may be unknown.

Which of the following statements is MOST accurate?

A statistic is a random variable whose value depends on the chosen random sample.

Which of the following are components of a control chart? Select all that apply.

Centerline Upper control limit (UCL) Lower control limit (LCL)

_________ involves dividing a population into mutually exclusive and exhaustive groups, and then selecting a random sample from these groups for analysis.

Cluster sampling

If a sample statistic consistently over- or under-estimates a population parameter, then there is ______.

bias

When a sample statistic is used to make inferences about a population parameter, it is referred to as a/an

estimator

When a firm applies statistical techniques to develop and maintain its ability to produce high-quality goods and services, it is implementing statistical ______.

quality control

A manufacturing production process is in control if the sample means are

randomly spread out between the control limits.

We use a calculated sample ______ to make inferences about an unknown population ______.

statistic, parameter Reason: Parameters describe populations; statistics describe samples.

In ______, the population is divided up into mutually exclusive and collectively exhaustive groups called strata. The sample consists of randomly-selected elements from each stratum.

stratified random sampling

Cluster sampling works best

when most of the variation in a population is within groups and not between groups.

Which of the following is considered an estimate?

x = 20

If p is the sample proportion from a sample that is large enough, then we can transform the proportion into its standard normal value as

z=p⎯⎯−pp(1−p)n√

The standard deviation of the sampling distribution of X is calculated as ______.

σ√n

The standard deviation of P equals

√p(1−p)n

A university's athletic program is considering changing its mascot. The SGA administers a survey to assess students' opinions by going to the business building. What type of bias is likely?

Selection Bias

True or false: Most statistical methods presume simple random samples.

True

True or false: If we had access to data that included the entire population, then the values of the parameters would be known and no statistical inference would be required.

True Reason: If you have data that describes the entire population, then the answers are perfect and no sampling or estimation is needed.

In statistical quality control, a tool used to monitor the behavior of a production process over time is called

a control chart.

A sample is

a subset of the population.

A particular value of an estimator is called a/an _______.

estimate

We use the finite population correction factor to

reduce the sampling variation of X⎯⎯⎯ and P.

Selection bias occurs when

there is a systematic exclusion of certain groups from consideration for the sample.

Stratified sampling is preferred to cluster sampling when the objective is

to increase precision.

In general, the control limits of a control chart are set at ______ standard deviations from the centerline.

3 Reason: 3 standard deviations captures almost the entire bell curve.

The general rule for using the finite correction factor is that the sample constitutes at least _____ of the population.

5%

As the population proportion deviates from p = 0.50, what happens to the sample size required in order to satisfy a normal approximation?

It gets larger.

As the sample size increases, what happens to the standard deviation of X?

It gets smaller.

What is a primary requirement of a "good" sample?

It is representative of the population we are trying to describe.

What kind of sampling is more likely to be used by political pollsters who want to ensure that each religious group is represented in the sample?

Stratified random sampling

In a statistical problem, a population consists of

all items of interest.

If the population from which the sample is drawn is normally distributed, then the sampling distribution of the sample mean is

always normally distributed.

Sample means or sample proportions being monitored by using a control chart should lie __________ .

between the upper and lower control limits.

The central limit theorem states that, for any distribution, as n gets larger, the sampling distribution of the sample mean becomes

closer to a normal distribution.

Social-desirability bias exists when

opinions that are socially unacceptable are not expressed.

Which one of the following is true about stratified and cluster sampling?

Stratified sampling provides greater precision.

Which of these is a characteristic of a "bad" sample?

The sample is not representative of the population being studied.

The branch of statistics that uses sample statistics to estimate a population parameter or test a hypothesis about such a parameter is BEST referred to as ________.

inferential statistics Reason: Descriptive statistics deals with charts, graphs, summary measures that describe data. Probability focuses on measuring the likelihood of obtaining certain sample outcomes from a known population.

A sampling distribution (select all that apply)

is the same as the probability distribution for a statistic. is distribution of a statistic that is calculated from all possible samples of size n from a population.

A firm uses acceptance sampling when

it produces a product and at the end of the process, inspects a portion.

The value of the finite population correction factor is alway

less than one.

The central limit theorem states that as n gets larger, the sampling distribution of the sample proportion

approaches a normal distribution.

A variation in production caused by a specific event or factor that can usually be identified and eliminated is called

assignable variation.

If X is normally distributed with expected value μ and standard deviation σ, then X is normally distributed with

expected value μ and standard deviation σ/√n.

The sample size required to approximate the normal distribution depends on

how much the population varies from normality.

As a general guideline, the normal distribution approximation can be used to describe the sampling distribution of the sample mean when

n ≥ 30.

The expected value of P is the

proportion of successes in the population.

When a sample of n observations that has the same probability of being selected from the population as any other sample of n observations is called a ______.

simple random sample

When a voter provides incorrect answers to a survey or poll because they think that others will look unfavorably on their choices, this is referred to as -desirability bias.

social

Assignable variation is caused by

specific events that can usually be identified and eliminated.

When a firm inspects the production process to determine at which point the process does not conform to standards, it is applying ______ for statistical quality control.

the detection approach

When the finite population correction factor is applied to the sample proportion, the resulting standard error for the sample proportion is equal to

√p(1−p)/n×√(N−n)/(N−1).