Statistics Exam

How does a qualitative variable differ from a quantitative variable?

A qualitative variable differs from a quantitative variable in that qualitative variables are typically expressed in words but may be coded into numbers later on for purposes of data processing, while a quantitative variable assumes meaningful numerical values.

To what does the phrase "descriptive statistics" refer?

Descriptive statistics is the summary of important aspects of a data set.

What three steps are essential for doing good statistics?

First, you must find complete data that is lacking any misrepresentation. Second, use the appropriate statistical tools. Third, clearly communicate numerical information into written language.

To what does the phrase "inferential statistics" refer?

Inferential statistics is the fast growing field within statistics that refers to drawing conclusions about populations based on samples.

Why is there a need for sampling?

It allows us to make inferences about various characteristics of the population.

What are the four major categories into which we may classify data?

Nominal Scale, Ordinal Scale, Interval Scale, and Ratio Scale. Nominal- Categorize or group data. Ordinal- Categorize and rank data with respect to some characteristic or trait. Interval- Categorize and rank data but we are also assured that the differences between scale values are equal. Ratio- All characteristics of the interval scale, and include a true zero point as the origin.

In which categories of data do qualitative fall?

Qualitative variables fall on the nominal and ordinal scales.

In which categories do quantitative variables fall?

Quantitative variables fall on the interval and ratio scales.

What is statistics?

Statistics is the methodology of extracting useful information from a data set.

What is the difference between a discrete and continuous variable?

The difference between a discrete and continuous variable is in regard to the quantitative variable. A discrete variable takes on individual distinct values, and a continuous variable can take on any value within an interval.

What is the difference between a population and a sample?

The difference between a population and a sample is the size of the data. A population is a large set of data, and a sample is a small set of data.

What is the difference between time-series and cross sectional data?

The difference between time-series data and cross-sectional data is in regard to the amount of subjects, and time periods, in which the data has been recorded. Time-series data refers to data collected by recording a characteristic of a subject over several time periods. Cross-sectional data refers to data collected by recording a characteristic of many subjects at the same point in time, or without regard to differences in time.