# Beginning of S1 Notes

[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...

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