Beginning of S1 Notes

Topics: Standard deviation, Median, Mean Pages: 4 (509 words) Published: January 20, 2013
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...