Mdm

Question 1

Calibration.

Answer 1

Marking a scale on a measuring measuring instrument
Tais involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values which must be applied. For eg placing a thermometer in melting ice to see whether it reads zero, in order to check it has been calibrated properly

Question 2

Accuracy

Answer 2

A measurement is considered accurate if it is judged to be close to the true value

Question 3

Data

Answer 3

Information either qualitative or quantitative that has been collected

Question 4

Quantitative data

Answer 4

is information about quantities; that is, information that can be measured and written down with numbers. Some examples of quantitative data are your height, your shoe size, and the length of your fingernails

Question 5

Qualitative data

Answer 5

is information about qualities; information that can’t actually be measured. Some examples of qualitative data are the softness of your skin, the grace with which you run, and the color of your eyes

Question 6

Measurement error

Answer 6

The difference between the measured value and the true value

Question 7

Anomaly

Answer 7

Values in a set of results which are judged not to be part of the variation caused by random uncertainty

Question 8

Random error

Answer 8

These cause readings to be spread about the true value due to results varying in an unpredictable way from one measurement to the next
They are present when any measurement is made, and cannot be corrected. The effect of random errors can be reduced by making more measurements and calculating a mean

Question 9

Systematic error

Answer 9

These cause readings to differ from the true value by a consistent amount each time a measurement is made.
Sources of systematic error can include the environment, methods of observation or instruments used.
Systematic errors cannot be dealt with by simple repeats. If a systematic error is suspected, the data collection should be repeated using a different technique or a different set of equipment, and the results compared.

Question 10

Zero error

Answer 10

Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero, eg the needle on an ammeter failing to return to zero when no current flows.
A zero error may result in a systematic uncertainty.

Question 11

Evidence

Answer 11

Data which has been shown to be valid.

Question 12

Fair test

Answer 12

A fair test is one in which only the independent variable has been allowed to affect the dependent variable.

Question 13

Hypothesis k

Answer 13

A proposal intended to explain certain facts or observations.

Question 14

Interval

Answer 14

The quantity between readings, eg a set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10 centimetres.

Question 15

Precision

Answer 15

Precise measurements are ones in which there is very little spread about the mean
value.
Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value.

Question 16

Prediction

Answer 16

A prediction is a statement suggesting what will happen in the future, based on observation, experience or a hypothesis.

Question 17

Range

Answer 17

The maximum and minimum values of the independent or dependent variables; important in ensuring that any pattern is detected.
For example a range of distances may be quoted as either: “From 10cm to 50 cm”
or
“From 50 cm to 10 cm”

Question 18

Repeatable

Answer 18

A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results.

Question 19

Reproducible

Answer 19

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

Question 20

Resolution j

Answer 20

This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.

Question 21

Sketch graph

Answer 21

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables. It will not have any points plotted and although the axes should be labelled they may not be scaled.

Question 22

True value

Answer 22

This is the value that would be obtained in an ideal measurement.

Question 23

Uncertainty

Answer 23

The interval within which the true value can be expected to lie, with a given level of confidence or probability, eg “the temperature is 20 °C ± 2 °C, at a level of confidence of 95 %.

Question 24

Validity

Answer 24

Suitability of the investigative procedure to answer the question being asked. For example, an investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants would not be a valid procedure if the temperature of the reactants was not controlled.

Question 25

Valid conclusion

Answer 25

A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.

Question 26

Variables

Answer 26

These are physical, chemical or biological quantities or characteristics.

Question 27

Categoric

Answer 27

Categoric variables have values that are labels. Eg names of plants or types of material.

Question 28

Continuous

Answer 28

Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of shrimp) or by measurement (eg light intensity, flow rate etc).

Question 29

Control

Answer 29

A control variable is one which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored.

Question 30

Dependant

Answer 30

The dependent variable is the variable of which the value is measured for each and every change in the independent variable.

Question 31

Independent

Answer 31

The independent variable is the variable for which values are changed or selected by the investigator.