Statistics

Levels of Measurement (4)

1. Nominal 2. Ordinal 3. Interval 4. Ratio (NOIR)

Sample (ch 1)

A subset of the population from which data are collected

If an outcome is favored over another, we call this _______.

Bias

When a study favors certain results.

Bias

A study in which data are obtained from every member of the population

Census

Systematic Sampling

Choosing a sample according to a pattern. Choosing every third or tenth member of an ordered population is an example of systematic sampling.

A market researcher interviews each member from each of the five randomly chosen neighborhoods throughout a city.

Cluster Sampling

Quantitative data that can take on any value in a given interval and are usually measurements

Continuous data

Quantitative data can be...

Continuous or discrete

gathers, sorts, summarizes, and displays the data

Descriptive Statistics

Branches of statistics

Descriptive and Inferential

Quantitative data that can take on only particular values and are usually counts

Discrete data

Simple Random Sampling

Each sample from the population has an equal chance of being selected.

Random Sampling

Every member of the population has an equal chance of being selected

Which study? Generates data to help identify cause-and-effect relationships

Experiment (Experimental Study)

uses descriptive statistics to estimate population parameters

Inferential Statistics

quantitative data that can be arranged in a meaningful order, and differences between data entries are meaningful

Interval level

Continuous data are usually...

Measurements, length and weight, not whole numbers all the time

qualitative data consisting of labels or names

Nominal level

occurs from sources other than the construction of the sample.

Non-Sampling Error(s)

Which study? Observes data that already exist.

Observational Study

qualitative data that can be arranged in a meaningful order, but calculations such as addition or division do not make sense

Ordinal level

Ch 1: Population

Particular group of interest

A substance that appears identical to the actual treatment but contains no intrinsic beneficial elements

Placebo

A tablet containing no actual medicine is an example of a _______.

Placebo

A response to the power of suggestion, rather than the treatment itself, by participants of an experiment

Placebo effect

Consist of labels or descriptions of traits

Qualitative data

Consist of counts or measurements

Quantitative data

Classify the following data. Indicate whether the data is qualitative or quantitative, indicate whether the data is discrete, continuous, or neither, and indicate the level of measurement for the data. The IQ scores of students at the local college. Are these data qualitative or quantitative? Are these data discrete or continuous? What is the level of measurement?

Quantitative, Discrete, Interval

A type of stratification in which certain characteristics of the population are preserved in the sample

Quota Sampling

quantitative data that can be ordered, differences between data entries are meaningful, and the zero point indicates the absence of something

Ratio level

Errors in a study resulting from the way the sample was chosen

Sampling Error

uses random samples drawn from each strata, or subgroup. This technique requires a prescribed proportion of members to be interviewed from each subgroup and is often used to ensure that a sample is representative of the population.

Stratified sampling

The number of times 12 out of 26 students on your floor order pizza in a week. What is the sample?

The 12 students on your floor

A group of subjects to which researchers apply a treatment in an experiment

Treatment group

Discrete data are usually...

counts and values, can take on only particular values and cannot take on the values in b/n (like number of pets b/c you can either have 2 or 3 pets, but not 2.75), whole numbers

Convenience Sampling

occurs when a researcher does not follow good sampling practices. For example, if you chose to interview the first ten people that went into a building because you were in a hurry to complete your study, you would be guilty of convenience sampling.

Cluster Sampling

randomly selects a sample of subgroups, or clusters, from the population. Each member from the clusters that have been chosen is then interviewed or chosen.

errors in the study resulting from the way the sample was chosen.

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