Embedded Files
Intro Stats: Islamic Approach -- Part 2: Probability and Statistics -
Lecture 1: Random Samples, Concept 3: Random Draw
S2: EXCEL-based methods for simple random draw
EXCEL function RANDBETWEEN(1,N) selects an integer at random between 1 and N, in such a way that all integers have equal chance of being selected.
Note of CAUTION -- EXCEL is a real world implementation and hence is IMPERFECT. ONLY our theoretical models are PERFECT, and all real world applications of the model are always imperfect. In particular EXCEL creates PSEUDO RANDOM numbers, which may show patterns that should not exist in real random numbers.
For a good discussion/explanation of True Randomness Versus Pseudo-Randomness look at website: RANDOM.ORG
Computers are deterministic machines and cannot general genuine random number. REAL WORLD processes can do better, but NONE can be perfect.
Above EXCEL sheet taken from Guiding Tech -- We start with a list of 13 names. We want to pick one student at random. That means all students must have equal chance 1/13 of being chosen. RANDBETWEEN(1,13) creates one integer between 1 and 13 in such a way that all integers are equally likely to be chosen. The CONCATENATE("A", RANDBETWEEN(1,13)) joins the two parts to create A? where ? is the random number generated by randbetween. Then the INDIRECT function finds out the entry in the cell A? -- in the spreadsheet above, it is clear that randbetween generated the random number 10, since the 10th row contains the name Josh, which is what is displayed in cell C2.
Page updated
Google Sites
Report abuse