Beginning of S1 Notes

Representation and Summary of data [10/09/12]
Histograms
* To be able to draw and interpret histograms. * Continuous Data:- * Measured [Rounded off to a particular degree of accuracy] * Time * Length * Speed – Velocity * Mass – Acceleration * Volume * Density * Area * Most suitable for a histogram.
The area of a histogram is proportional to its frequency.
Area ∞ Frequency Class Width = UCB – LCB
Height of each rectangle is called the frequency density: Frequency Density = FrequencyClass Width
Stem and Leaf diagrams (S+L) [20/09/12]
Stem and Leaf * Key is essential! * Display discrete data * Continuous is ok but round it off to either nearest whole number or 1/2 d.p) * Can be plotted into a box plot * Can find * Median (Q₂) * Range * Quartiles (Q₁, Q₂, Q₃) * Inter-quartile Range * Excludes outliers * Middle 50% of data * Percentiles * Outliers (Extreme values) * Ordered data
Cumulative Frequency Diagrams [27/09/12]
Aims - To complete cumulative frequency curve and step diagrams. - Quartiles using calculation

Cumulative frequency diagrams: * Data used is usually continuous. * Sigmoid Curve (N.B. – Capital Sigma = Σ, Lower-case Sigma = ς) * Estimate - Q₁, Q₂, Q₃, P25%, P95% * Plot points at highest boundary of each class. * Cumulative Frequency taken from 0≤x≤"n" * Used for medians, means, inter-quartile range and percentiles. * Grouped data.

* Step cumulative frequency. * Recognise this graph! * Allows you to see main differences between the points plotted * Step cumulative frequency. * Recognise this graph! * Allows you to see main