Measurement and Scales of Measurement

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Questions and Answers

Which type of validity checks if measurements are drawn from the relevant course or program material?

Predictive Validity

Face Validity

Content Validity (correct)

Construct Validity

What does reliability in measurement ensure?

The values are consistent or reproducible (correct)

The measurements appear to measure what is intended

The values reflect the underlying concept

The measurements predict target behavior

Which type of validity focuses on the relationship between the measurement and other established measurements?

Face Validity

Construct Validity

Concurrent Validity (correct)

Content Validity

What is the purpose of Test-Retest Reliability?

To administer the same test twice and correlate scores Signup and view all the answers

Which type of reliability is assessed by comparing agreement between two or more raters?

Inter-Rater Reliability Signup and view all the answers

What is the main goal of validity in the measurement process?

To show that values reflect the underlying construct Signup and view all the answers

Which type of validity predicts some target behavior based on measurement?

Predictive Validity Signup and view all the answers

What does Split-Half Reliability involve?

Dividing the test into two parts and correlating the scores Signup and view all the answers

What does the term 'variables' refer to in measurement?

Properties of objects that can take on different values Signup and view all the answers

Which scale of measurement represents an ordered series of relationships?

Ordinal Signup and view all the answers

What characterizes a ratio scale of measurement?

Equal units with a meaningful absolute zero Signup and view all the answers

Which of these is an example of an interval scale?

Fahrenheit temperature Signup and view all the answers

What does accuracy in measurement refer to?

Proximity of measured quantities to their true values Signup and view all the answers

What is the primary purpose of measurement scales?

To substitute precise numbers for imprecise words Signup and view all the answers

How does precision differ from accuracy in measurements?

Precision denotes consistency among measurements, while accuracy denotes closeness to the true value. Signup and view all the answers

What type of data does a nominal scale typically represent?

Categorical data used simply as identifiers Signup and view all the answers

What are common types of measurement errors?

Random errors, systematic errors, and gross errors Signup and view all the answers

Which type of error remains after gross and systematic errors are eliminated?

Random errors Signup and view all the answers

What is the purpose of a filter in data acquisition?

To separate the wanted signal from noise Signup and view all the answers

What is the significance of sample rate in data acquisition?

It represents the digitalization of data in discrete steps. Signup and view all the answers

Which of the following best describes systematic errors?

They can be checked and adjusted, maintaining the same sign. Signup and view all the answers

What role do buffer blocks play in data acquisition?

They help manage rapid data collection in PC RAM. Signup and view all the answers

What defines polled (asynchronous) acquisition in data gathering?

It allows applications to sample data one at a time. Signup and view all the answers

Why is it challenging to estimate the true value in measurements with errors?

Measurement errors prevent identifying the true value. Signup and view all the answers

What type of data acquisition can achieve faster sample rates than polled acquisition?

Interrupt driven acquisition Signup and view all the answers

Which acquisition mode allows data to be streamed to disk only in binary format at high rates?

Continuous acquisition Signup and view all the answers

What is the main limitation of burst acquisition?

It depends on the speed of the device and buffer size Signup and view all the answers

What type of noise affects a circuit by traveling through the air?

Radiated noise Signup and view all the answers

How can conducted noise effectively be reduced in circuits?

Through shielding or filtering Signup and view all the answers

What is a characteristic of time delays in data acquisition?

A small delay is inherent in both reading and processing Signup and view all the answers

At what sample rate is continuous data acquisition typically achieved?

Over 100,000 samples per second Signup and view all the answers

What factor is NOT necessary for radiated noise to couple into a circuit effectively?

Distance from the noise source Signup and view all the answers

Study Notes

Measurement

Measurement involves assigning numeric values to objects or events to understand a variable.
Units are used to define quantities of length, area, volume, temperature, pressure, and more.
Variables are properties of objects that can take on different values.
Precision refers to the consistency of measurements, while accuracy is the nearness to the true value.

Scales of Measurement

Nominal Scale: Numbers are used as identifiers or names, and order doesn't matter.
- Examples: Numbers on sports jerseys, social security numbers.
Ordinal Scale: Represents a rank order, with order being significant but not the distance between values.
- Examples: Ranking in a competition, Likert-type scales (e.g., strongly agree, agree, disagree).
Interval Scale: Represents quantity with equal units, but zero is arbitrary, not absolute.
- Examples: Fahrenheit temperature scale, measurement of sea level.
Ratio Scale: Represents quantity with equal units, and has a true zero point.
- Examples: Height, weight, length of wood.

Reliability and Validity

Reliability: Consistency and reproducibility of measurements.
- Types:
  - Test-Retest: Administering the same test twice and correlating scores.
  - Alternate: Administering two forms of a test and correlating scores.
  - Split-Half: Splitting a test into halves and correlating scores.
  - Inter-Rater: Comparing ratings from two or more raters and correlating scores.
Validity: Ensuring that measurements truly reflect the underlying concept.
- Types:
  - Face: Measurements appear to measure what is intended.
  - Content: Measurements are drawn from relevant course or program material.
  - Concurrent: Measurement is similar to other established measurements.
  - Construct: Measurements support a psychological concept by predicting behavior.
  - Predictive: Measurements predict some target behavior.

Measurement Errors

Gross Errors (Mistakes): Large errors, easily identifiable, and should be eliminated before adjustment.
Systematic Errors: Follow a mathematical function, can be checked and adjusted, tend to have a consistent sign.
- Examples: Confounding variables or bias that artificially influence measurement in one direction.
Random Errors: Remain after eliminating gross and systematic errors, follow probability laws.
- Cannot be completely computed or eliminated, but can be adjusted.

Data Acquisition Parameters

Data Acquisition: Sampling continuous real-world information to generate computer processable data.
Sample Rate: The frequency at which data is sampled, determining the resolution of the digital representation.
Filters: Separate desired signals from unwanted noise.
Buffer Blocks: Portions of RAM used to store data rapidly and maintain timing accuracy.

Acquisition Types

Polled (Asynchronous): Application determines when to sample data from the device, one sample at a time.
Interrupt Driven (Synchronous/Buffered): Acquires data in blocks, achieving faster acquisition rates.

Acquisition Modes

Continuous: Data acquisition at high rates, often streamed to disk in binary format.
Burst: Even faster, limited by device speed and buffer size.

Noise

Radiated Noise: Travels through the air as radio waves, impacting circuits or enclosures with dimensions near the wavelength.
Conducted Noise: Enters circuits through wires, affecting signal or power supply wires.
- Reduction strategies include shielding and filtering.

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Description

This quiz covers the concepts of measurement, including the definitions of precision and accuracy. It also explores different scales of measurement such as nominal, ordinal, interval, and ratio scales, providing examples for each. Test your understanding of how numeric values are assigned to various objects and events.