Quiz 1 - Unit 1

What is ratio data?

Ratio data is interval data with a natural zero point. For example, time is ratio since 0 time is meaningful. Degrees Kelvin has a 0 point (absolute 0) and the steps in both these scales have the same degree of magnitude.

Numerical or Summary measures are______________________?

Values that are calculated; e.g mean, standard deviation.

A characteristic that may assume different values for different elements is called a _______________________.

Variable.

Simple random sampling is _____________.

a method of selecting items from a population such that every possible sample of a specific size has an equal chance of being selected. Sampling here may be with or without replacement.

Cluster sampling is ________________________________.

a simple random sample of groups or cluster of elements. Cluster sampling is useful when it is difficult or costly to generate a simple random sample.

In an Experimental Study investigators ____________________________________.

apply treatments to experimental units (people, animals, plots of land, etc.) and then proceed to observe the effect of the treatments on the experimental units.

In a Randomized experiment investigators __________________________________.

control the assignment of treatments to experimental units using a chance mechanism (like the flip of a coin).

Quota sampling is ________________________________.

when the decision maker requires the sample to contain a certain number of items with a given characteristic.

Convenience sampling is__________________________________.

when the decision maker selects a sample from the population in a manner that is relatively easy and convenient. (may include volunteer sampling)

Judgement sampling is _____________________________.

when the person taking the sample has direct or indirect control over which items are selected for the sample.

Information that has been recorded but not yet organised is called ___________________________.

Raw data.

Systematic sampling is ___________________________.

a method where every nth element is chosen when data is arranged in random order.

What are the two types of Data Collection?

1. Cross-Section Data 2. Time-Series Data

What are some methods of collecting Primary Data?

1. Direct personal interviews 2. Focus group 3. Telephone interviews 4. Mail questionnaires 5. Door-to-Door Survey 6. Experiments are some of the sources for collecting primary data

What are the four levels of measurement?

1. Nominal 2. Ordinal 3. Interval data 4. Ratio data

What are the two types of Variables or Data?

1. Qualitative Variables 2. Quantitative Variables

What are the two sources of data?

1. Secondary data and 2. Primary data

What is a survey that includes every member of the population?

A census

What is bias?

Bias is the intentional or unintentional alteration of data and/or analysis results. Bias occurs when the data is misinterpreted or if a critical part is left out. Bias also occurs through the selection of words that may slant or taint the data or the analysis. The tendency of a pattern of errors to influence data in an unrepresentative way.

A specific subject under consideration is called an ___________________.

Element or member.

What is interval data?

Interval data is like ordinal except we can say the intervals between each value are equally split. The most common example is temperature in degrees Fahrenheit. The difference between 29 and 30 degrees is the same magnitude as the difference between 78 and 79 . With attitudinal scales you usually see on a survey, these are rarely interval, although many points on the scale likely are of equal intervals.

What is statistics?

Statistics is defined as the science of collecting, organizing, presenting, analyzing and interpreting numerical data for the purpose of assisting in making a more effective decision.

In an Observational Study investigators ____________________________________________.

observe subjects and measure variables of interest without assigning treatments to the subjects. The treatments that each subject receives is determined beyond the control of the investigator.

Information that is collected from a portion of the population is called a _______________________.

sample survey

What is a Representative sample?

A representative sample is a sample chosen so that the characteristics of the sample closely resemble those of the population from which it was chosen.

What is random sampling?

A sample where every member of the population has some chance of being selected.

What is non-random sampling?

A sample where some members of the population have no chance of being selected.

A collection of observations on one or more variables is called a ______________________________.

Data set.

Descriptive statistics is a method used to generalize from a sample to a population. Sample data is used to predict and make decisions about a population. True or false?

False. Descriptive Statistics is concerned with describing data: tables, graphs, charts and summary calculations.

Inferential statistics is concerned with describing data: tables, graphs, charts and summary calculations. True or false?

False. Inferential statistics is a method used to generalize from a sample to a population. Sample data is used to predict and make decisions about a population.

Primary data is data which are already available. True or false?

False. Primary data is data that is collected by the researcher himself.

Qualitative Variables are numerical variables and can be measured. Examples include your height, the balance in your checking account, number of children in your family. True or false?

False. Qualitative Variables are non-numeric variables and can't be measured. They are also called categorical data. Examples include gender, religious affiliation, country of birth, satisfaction level. Qualitative variables may be nominal or ordinal.

Quantitative Variables are non-numeric variables and can't be measured. They are also called categorical data. Examples include gender, religious affiliation, country of birth, satisfaction level. Qualitative variables may be nominal or ordinal. True or False?

False. Quantitative Variables are numerical variables and can be measured. Examples include your height, the balance in your checking account, number of children in your family.

Secondary data is data that is collected by the researcher himself. True or false?

False. Secondary data is data which are already available. It is less expensive but may not satisfy your needs.

The population is some elements, objects, items or individuals in a group. True or false?

False. The population is the entire group of elements (objects, items, individuals) under study.

What is Nominal data?

Nominal basically refers to categorical data such as name of your school, type of car you drive or name of a book. This one is easy to remember because nominal sounds like name (they have the same Latin root)

What is the Population Parameter?

Numerical (summary) measures calculated for a population.

What is the Sample statistic?

Numerical (summary) measures calculated for a sample.

The specific value of a variable collected for an element is called an ______________________________.

Observation.

What is Ordinal data?

Ordinal refers to quantities that have a natural ordering. The ranking of favorite sports, the order of people's place in a line, the order of runners finishing a race or more often the choice on a rating scale from 1 to 5. With ordinal data you cannot state with certainty whether the intervals between each value are equal. For example, we often using rating scales. This is also an easy one to remember, ordinal sounds like order.

What are the two types of Quantitative Data?

Quantitative variables are either 1. discrete (which can assume only certain values, and there are usually "gaps" between the values, such as the number of bedrooms in your house) These are counted. 2. continuous (which can assume any value within a specific range, such as the air pressure in a tire.) These are measured.

What is a survey?

The process of collecting information from elements

Cross-section data id data collected on different elements at the same point of time or the same period of time. True or False?

True

There are two types of statistics: Descriptive statistics and Inferential statistics. True or false?

True

Time-series data is data collected on the same element for the same variable at different points in time or for different periods of time. True or False?

True

A sample is a portion of the population being studied. True or false?

True.

Sampling error is caused by _____________________________.

observing a sample instead of the whole population. It can be found by subtracting the value of a parameter from the value of a statistic.

Stratified Random Sampling is ______________________________.

obtained by selecting simple random samples from strata (or mutually exclusive sets). Some of the criteria for dividing a population into strata are: sex, age, occupation, religion.

When a population element can be selected more than one time, we are ___________________________.

sampling with replacement.

When a population element can be selected only one time, we are __________________________.

sampling without replacement

Nonsampling error is an error in ____________________________________.

statistical analysis caused by human error. It includes data entry errors, biased questions in questionnaire, false information given by respondents.

Snowball sampling is _____________________________________.

when existing study subjects recruit future subjects from among their acquaintances. Thus the sample group appears to grow like a rolling snowball.