Across
- 3. 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. May result in a systematic uncertainty.
- 5. When only the independent variable has been allowed to affect the dependent variable.
- 7. Data which has been shown to be valid.
- 8. variables have values that are labels, eg names of plants or types of material.
- 10. These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next. 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 new mean.
- 13. These cause readings to differ from the true value by a consistent amount each time a measurement is made. Sources of error can include the environment, methods of observation or instruments used. They cannot be dealt with by simple repeats
- 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.
- 18. A statement supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.
- 21. variables 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, low rate etc). Previously known as discrete variables.
- 22. This is the value that would be obtained in an ideal measurement.
- 23. This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.
- 25. the variable for which values are changed or selected by the investigator
- 26. A measurement is this if the original experimenter repeats the investigation using same method and equipment and obtains the same results. Previously known as reliable.
Down
- 1. A proposal intended to explain certain facts or observations.
- 2. a statement suggesting what will happen in the future, based on observation, experience or a hypothesis.
- 4. The difference between a measured value and the true value.
- 6. A measurement result is considered this if it is judged to be close to the true value.
- 9. measurements where there is very little spread about the mean value – it gives no indication of how close results are to the true value.
- 11. a variable 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.
- 12. These are values in a set of results which are judged not to be part of the variation caused by random uncertainty.
- 15. 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.
- 16. Marking a scale on a measuring instrument. This involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values, which must be applied.
- 17. A measurement is this if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained. Previously known as reliable.
- 18. These are physical, chemical or biological quantities or characteristics.
- 19. The interval within which the true value can be expected to lie. Whenever a measurement is made, there will always be some doubt about the result obtained.
- 20. variable of which the value is measured for each and every change in the independent variable.
- 24. 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 10 cm to 50 cm' or 'From 50 cm to 10 cm'.