The Ministry is migrating nzmaths content to Tāhurangi.
Relevant and up-to-date teaching resources are being moved to Tāhūrangi (tahurangi.education.govt.nz).
When all identified resources have been successfully moved, this website will close. We expect this to be in June 2024.
e-ako maths, e-ako Pāngarau, and e-ako PLD 360 will continue to be available.
For more information visit https://tahurangi.education.govt.nz/updates-to-nzmaths
The reasons for differences seen in the values of a variable. Some of these reasons are summarised in the following paragraphs.
Variation is present everywhere and is in everything. When the same variable is measured for different individuals there will be differences in the measurements, simply due to the fact that individuals are different. This can be thought of as individual-to-individual variation and is often described as natural or real variation.
Repeated measurements on the same individual may vary because of changes in the variable being measured. For example, an individual’s blood pressure is not exactly the same throughout the day. This can be thought of as occasion-to-occasion variation.
Repeated measurements on the same individual may vary because of some unreliability in the measurement device, such as a slightly different placement of a ruler when measuring. This is often described as measurement variation.
The difference in measurements of the same quantity for different individuals, apart from natural variation, could be due to the effect of one or more other factors. For example, the difference in growth of two tomato plants from the same packet of seeds planted in two different places could be due to differences in the growing conditions at those places, such as soil fertility or exposure to sun or wind. Even if the two seeds were planted in the same garden there could be differences in the growth of the plants due to differences in soil conditions within the garden. This is often described as induced variation.
Variation occurs in all sampling situations. Suppose a sample is taken and a sample statistic, such as a sample mean, is calculated. If a second sample of the same size is taken from the same population, it is almost certain that the sample mean calculated from this sample will be different from that calculated from the first sample. If further sample means are calculated, by repeatedly taking samples of the same size from the same population, then the differences in these sample means illustrate sampling variation.
Curriculum achievement objectives references
Statistical investigation: Levels 5, 6, (7), (8)
