Ch.1

Data at the ordinal level are quantitative only. True or False

False. Data at the ordinal level can be qualitative or quantitative.

More types of calculations can be performed with data at the nominal level than with data at the interval level True or False

False. More types of calculations can be performed with data at the interval level than with data at the nominal level.

The method for selecting a stratified sample is to order a population in some way and then select members of the population at regular intervals. True or False

False. The method for selecting a systematic sample is to order a population in some way and then select members of the population at regular intervals.

Using a systematic sample guarantees that members of each group within a population will be sampled. True or False

False. Using a stratified sample guarantees that members of each group within a population will be sampled.

Observational studies are sometimes referred to as natural experiments. Explain what this means.

In an observational​ study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions.

What is the difference between an observational study and an​ experiment?

In an​ experiment, a treatment is applied to part of a population and responses are observed. In an observational​ study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions.

Select all the levels of measurement for which data can be qualitative. A. Nominal .B. Interval C. Ratio D. Ordinal

Nominal Ordinal

Ordinal Level of measurment

Qualitative and quantitative. Data at this level can be arranged in order, or ranked, but differences between data entries are not meaningful.

What is replication in an​ experiment? Why is replication​ important?

Replication is repetition of an experiment under the same or similar conditions. Replication is important because it enhances the validity of the results.

A placebo is an actual treatment. True or False

The statement is false. A placebo is a fake treatment.

A sample statistic will not change from sample to sample True or False

The statement is false. A sample statistic can change from sample to sample. A parameter will not change*

Data at the ratio level cannot be put in order.

The statement is false. A true statement is​ "Data at the ratio level can be placed in a meaningful​ order."

For data at the interval​ level, you cannot calculate meaningful differences between data entries True or False

The statement is false. A true statement is​ "For data at the interval​ level, you can calculate meaningful differences between data​ entries."

A​ double-blind experiment is used to increase the placebo effect. True or False

The statement is false. Double blinding is used to decrease the placebo effect.

Parameter

a numerical description of a population characteristic

Population

collections of all out comes, responses, measurements, or counts that are of interest.

Statistics

the science of collecting, organizing, analyzing, and interpreting data in order to make decisions.

Two types of data sets?

Population, Sample

Sample

a subset, or part, of a population

Data

Consists of information coming from observations, counts, measurements, or responses.

random sample

one in which every member of the population has an equal chance of being selected.

What is the difference between a census and a​ sampling?

A census includes the entire population. A sampling includes only part of the population.

Double-blind experiment

neither the experimenter nor the subjects know if the subjects are receiving a treatment or a placebo

What is the difference between a random sample and a simple random​ sample?

With a random​ sample, each individual has the same chance of being selected. With a simple random​ sample, all samples of the same size have the same chance of being selected.

statistic

a numerical description of a sample characteristic

simple random sample

a sample in which every possible sample of the same size has the same chance of being selected.

Blinding

a technique where the subjects do not know whether they are receiving a treatment or a placebo

ratio level of measurment

can be ordered, and meaning full differences between data entries can be calculated. Has inherent zeros

interval level of measurement

can be ordered, and meaning full differences between data entries can be calculated. No inherent zeros

nominal level of measurment

qualitative only. Data at this level are categorized using names, labels, or qualities. No mathematical computations can be made at this level.

convenience sample

sample consisting of only members of the population that are easy to get to.

Descriptive statistics

the branch of statistics that involves the organization, summarization, and display of data.

Inferential statistics

the branch of statistics that involves using a sample to draw conclusions about a population.