Summarizing and Presenting Data

Statistics The scientific study of numerical data based upon variation in nature.

Some Definitions Observations Datum/Data Variable Statistical Population Sample Observations Datum/Data Variable Statistical Population Sample

Descriptive Statistics Statistics of Location –Average (Mean) –Median –Mode Statistics of Dispersion –Range –Standard Deviation Statistics of Location –Average (Mean) –Median –Mode Statistics of Dispersion –Range –Standard Deviation

Calculating an Average

= = 28 = = 28 Calculating an Average i X i i X i = X 1 + X 2 + X 3 + X 4 + X 5 ∑X i i=1 n n

Calculating an Average i X i i X i = (X 1 + X 2 + X 3 + X 4 + X 5 )/n = (∑X i )/n i=1 n n X X = ( )/5 = 28/5 = 5.6 = ( )/5 = 28/5 = 5.6

Calculating a Standard Deviation

X i (X i )

Calculating a Standard Deviation

2 (

(

Presenting Tables AVERAGE DIET WEIGHTLENGTH TYPE (g) (cm) high fat low fat AVERAGE DIET WEIGHTLENGTH TYPE (g) (cm) high fat low fat TABLE I The Effects of High Fat Versus Low Fat Diets on Rat Weights and Lengths TABLE I The Effects of High Fat Versus Low Fat Diets on Rat Weights and Lengths

Graphing Data

Presenting Graphs frequency Figure 1.Frequency histogram of number of seeds per pod for koa haole, Leucaena leucocephala, seed pods.

Figure 2.Weight-length relationships of koa haole, Leucaena leucocephala, seed pods. weight (g) Presenting Graphs

Rules for Tables and Figures Each figure or table must be identified by a figure or table reference number Each figure or table must have a clear descriptive title. If the figure or table refers to biological specimens, then the scientific names of these specimens are generally referred to in the title Each figure or table must be identified by a figure or table reference number Each figure or table must have a clear descriptive title. If the figure or table refers to biological specimens, then the scientific names of these specimens are generally referred to in the title

Rules for Tables and Figures In tables, column/row headings should clear identify the variable and its units of measure In figures such as graphs, the axes should be clearly labeled and the units of measure indicated In figures, such as diagrams or maps, the pertinent features should be clearly labeled In tables, column/row headings should clear identify the variable and its units of measure In figures such as graphs, the axes should be clearly labeled and the units of measure indicated In figures, such as diagrams or maps, the pertinent features should be clearly labeled

Rules for Tables and Figures Do not cram figures and graphs into a small space on a sheet of paper; try to fill up a whole sheet of paper A general rule of thumb is that each figure/table should be able to stand alone without forcing the reader to read additional text to understand it Do not cram figures and graphs into a small space on a sheet of paper; try to fill up a whole sheet of paper A general rule of thumb is that each figure/table should be able to stand alone without forcing the reader to read additional text to understand it