Bsc150; Week 8

Front 1

Psychologist Stanley Smith Stevens (1946) argued that not all scales are the same. What are the four different 'levels of measurement'?

Back 1

In order of increasing value we have:
NOMINAL – the numbers are only used to distinguish between individuals (e.g. the numbers on the backs of football players) .
ORDINAL – the numbers are only allowed to be sorted according to some criterion. We can say A is ahead of B, but we cannot know by how far. (e.g. Olympic medals: gold is given to the best performer, silver to the next best and bronze to the next best).
INTERVAL – the numbers can be sorted and we can say how far apart they are on an arbitrary scale. (e.g. temperature measured on a Celsius thermometer. This scale has no ‘natural’ zero point.)
RATIO – the numbers have all of the above meanings, but the scale has a ‘natural’ zero point. (e.g. temperature measured on a Kelvin scale has an absolute zero – the point at which all thermal motion of molecules ceases!

Front 2

Define: NOMINAL

Back 2

NOMINAL – the numbers are only used to distinguish between individuals (e.g. the numbers on the backs of football players) .

Front 3

Define: ORDINAL

Back 3

ORDINAL – the numbers are only allowed to be sorted according to some criterion. We can say A is ahead of B, but we cannot know by how far. (e.g. Olympic medals: gold is given to the best performer, silver to the next best and bronze to the next best).

Front 4

Define: INTERVAL

Back 4

INTERVAL – the numbers can be sorted and we can say how far apart they are on an arbitrary scale. (e.g. temperature measured on a Celsius thermometer. This scale has no ‘natural’ zero point.)

Front 5

Define: RATIO

Back 5

RATIO – the numbers have all of the above meanings, but the scale has a ‘natural’ zero point. (e.g. temperature measured on a Kelvin scale has an absolute zero – the point at which all thermal motion of molecules ceases!

Front 6

What do scores on an INTERVAL SCALE represent?

Back 6

Scores on an interval scale represent their rank order and also their distance from other scores.

Front 7

Define: The SI System

Back 7

The SI System is a system of metric units of measurement built around seven base units and a larger number of derived units.

Front 8

What are the 7 SI base units and what are they used for?

Back 8

The SI base units and their physical quantities are:

* metre for length.
* kilogram for mass.
* second for time.
* ampere for electric current.
* kelvin for temperature.
* candela for luminous intensity.
* mole for the amount of substance.

Front 9

What is meant by TRUENESS?

Back 9

Trueness is how close the average of our measurements comes to the true value we want. (also known as Validity in some disciplines)

(Note: Good trueness and good precision = good accuracy)

Front 10

What is meant by PRECISION?

Back 10

Precision is how closely our repeated measurements agree.

(Note: Good trueness and good precision = good accuracy)

Front 11

Define: PROBABILITY and ODDS

Back 11

Probability is just a number between 0 and 1. It is a way of expressing how likely some event is to happen.

A related concept is odds – which might be the ratio of the probability of something happening to the probability of it not happening, (written as e.g. 1: 6).

Front 12

FREQUENTIST Vs. SUBJECTIVIST (in relation to probability)

Back 12

Frequentists say probability is a way of recording how often a certain event happens as fraction of all the possible happenings.

Subjectivists say it’s really a human judgement about whether or not to be surprised by what comes up.

Front 13

Define: INFERENTIAL STATISTICS

Back 13

Inferential statistics is concerned with making predictions or inferences about a population from observations and analyses of a sample.

Inferential statistics ALWAYS have probabilities associated with them.

Front 14

Define: DESCRIPTIVE STATISTICS

Back 14

Descriptive statistics is the term given to the analysis of data that helps describe, show or summarize data in a meaningful way such that, for example, patterns might emerge from the data.

Front 15

What did Eugene Wigner mean by the “unreasonable effectiveness of mathematics” in the natural sciences?

Back 15

That abstract mathematical concepts are surprisingly powerful in allowing scientists to detect and understand laws of nature.

Front 16

What was the main reason for scientists in every nation adopting the SI metric system of measurement?

Back 16

It simplifies scientific communication when everyone uses standard definitions and units.

Front 17

Define: NULL HYPOTHESIS

Back 17

The null hypothesis refers to a general statement or default position that there is no relationship between two measured phenomena.

The null hypothesis is that there is no REAL difference, and any apparent difference that may be seen is due to chance. A null hypothesis is framed in a way that is able to be falsified. It may be rejected or disproved, but never accepted or proven.