Stats 1-3

What is a​ frame?

A frame is a list of the individuals in the population being studied.

What is a​ cross-sectional study?

Cross-sectional studies are observational studies that collect information about individuals at a specific point in time or over a very short period of time.

True or False. When conducting a cluster​ sample, it is better to have fewer clusters with more individuals when the clusters are heterogeneous.

​True, because when the clusters are​ heterogeneous, they are scaled down versions of the population.

Which allows the researcher to claim causation between an explanatory variable and a response​ variable?

designed experiment

A(n) _________ is a person or object that is a member of the population being studied. Choose the correct answer below.

individual

define sampling bias

is a bias in which a sample is collected in such a way that some members of the intended population are less likely to be included than others.

define matched pair design

is a special case of a randomized block design. It can be used when the experiment has only two treatment conditions; and subjects can be grouped into pairs, based on some blocking variable. Then, within each pair, subjects are randomly assigned to different treatments.

define completely randomized design

is probably the simplest experimental design, in terms of data analysis and convenience. With this design, subjects are randomly assigned to treatments. Treatment. Placebo. Vaccine.

define response bias

is the tendency of a person to answer questions on a survey untruthfully or misleadingly. For example, they may feel pressure to give answers that are socially acceptable.

Determine the level of measurement of the variable. Makes of a car

nominal

Determine whether the variable is qualitative or quantitative. Grams of carbohydrates in a donut Is the variable qualitative or​ quantitative?

The variable is quantitative because it is a numerical measure.

What is a Pareto​ chart?

A Pareto chart is a bar graph whose bars are drawn in decreasing order of frequency or relative frequency.

What is a closed​ question? What is an open question?

A closed question has fixed choices for​ answers, whereas an open question is a​ free-response question.

What is an observational​ study?

An observational study measures the value of the response variable without attempting to influence the value of either the response or explanatory variables.

Define treatment

Any combination of the values of the factors​ (explanatory variables)

​Define experimental unit.

A​ person, object, or some other​ well-defined item upon which a treatment is applied

What is a​ case-control study?

Case-control studies are observational studies that are​ retrospective, meaning that they require individuals to look back in time or require the researcher to look at existing records.

True or false. When taking a systematic random sample of size​ n, every group of size n from the population has the same chance of being selected.

False, because certain groups would never be selected.

True or False. A simple random sample is always preferred because it obtains the same information as other sampling plans but requires a smaller sample size.

False, because other sampling techniques may provide more information for less cost than a simple random sample.

True or False. Inferences based on voluntary response samples are generally not reliable.

Inferences based on voluntary response samples are generally not reliable.

Determine whether the quantitative variable is discrete or continuous. Percentage of a car's surface which is rusted Is the variable discrete or​ continuous?

The variable is continuous because it is not countable.

Distinguish between nonsampling error and sampling error.

Nonsampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population.

What does it mean when sampling is done without​ replacement?

Once an individual is​ selected, the individual cannot be selected again.

What is replication in an​ experiment?

Replication is applying each treatment to more than one experimental unit.

Define nonresponse bias

Sometimes, in survey sampling, individuals chosen for the sample are unwilling or unable to participate in the survey.

Grouping together similar experimental units and then randomly assigning the experimental units within each group to a treatment is called

blocking

To determine customer opinion of their check dash in service​, American Airlines randomly selects 60 flights during a certain week and surveys all passengers on the flights. What type of sampling is​ used?

cluster

is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.

cluster sample

A frequency distribution lists the --------of occurrences of each category of​ data,

number

Determine the level of measurement of the variable below. Highest degree conferred left parenthesis high school comma bachelor's comma and so on right parenthesis

ordinal

is a numerical summary of a population.

parameter

relative frequency distribution lists the ----- of occurrences of each category of data.

proportion

Apple wants to administer a satisfaction survey to its current customers. Using their customer​ database, the company randomly selects 40 customers and asks them about their level of satisfaction with the company. What type of sampling is​ used?

simple random

is a numerical summary of a sample.

statistic

is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group.

stratified sample

define randomized blocking design

the experimenter divides subjects into subgroups called blocks, such that the variability within blocks is less than the variability between blocks. Then, subjects within each block are randomly assigned to treatment conditions.

_________ are the characteristics of the individuals of the population being studied.

variables

What does it mean when an observational study is​ retrospective?

A retrospective study requires that individuals look back in time or require the researcher to look at existing records.

True or False. When obtaining a stratified​ sample, the number of individuals included within each stratum must be equal.

False. Within stratified​ samples, the number of individuals sampled from each stratum should be proportional to the size of the strata in the population.

What is a designed​ experiment?

A designed experiment is when a researcher assigns individuals to a certain​ group, intentionally changing the value of an explanatory​ variable, and then recording the value of the response variable for each group.

What does it mean when a part of the population is​ under-represented?

A part of the population is​ under-represented when it is proportionally smaller in a sample than in its population.

What does it mean when an observational study is​ prospective?

A prospective study collects the data over time.

Define statistics.

Statistics is the science of​ collecting, organizing,​ summarizing, and analyzing information to draw a conclusion and answer questions. In​ addition, statistics is about providing a measure of confidence in any conclusions.

To determine her breathing rate​, Miranda divides up her day into three​ parts: morning,​ afternoon, and evening. She then measures her breathing rate at 3 randomly selected times during each part of the day.

Stratified

To estimate the percentage of defects in a recent manufacturing​ batch, a quality control manager at Daimler minus Chrysler selects every 15th van that comes off the assembly line starting with the eighth until she obtains a sample of 80 vans. What type of sampling is used?

Systematic

Which sampling method does not require a​ frame?

Systematic