The tragedy of life is not that it ends so soon, but that we wait so long to begin it. –by W. M. Lewis So, which is the exit style you prefer, in the following 3 macros (which are all valid SAS codes): /*#1 if branch*/ %macro tragedy_of_life1(ds); %if %sysfunc(exist(&ds)) %then %do; proc […]
Tag: Logic
Frequentist or Baysian
A latest updated post on Freakonomics, Beware the Weasel Word “Statistical” in Statistical Significance!, seemed to attempt to challenge frequentist statistics by Bayesian. I have no research on Bayesian and won’t jump to the debates. I’d rather to use this case to apply the Dragon’s Teeth and Fleas logic of hypothesis testing (at least I […]
Example 9.26: More circular plotting
SAS’s Rick Wicklin showed a simple loess smoother for the temperature data we showed here. Then he came back with a better approach that does away with edge effects. Rick’s smoothing was calculated and plotted on a cartesian plane. In this entry we’…
Example 9.25: It’s been a mighty warm winter? (Plot on a circular axis)
People here in the northeast US consider this to have been an unusually warm winter. Was it?The University of Dayton and the US Environmental Protection Agency maintain an archive of daily average temperatures that’s reasonably current. In the case o…
Recursion: Biblical Evidences
To Iterate is Human, to Recurse, Divine.
–by L. Peter Deutsch, creator of Ghostscript. (I also love his saying “The best thing about a Boolean is even if you are wrong, you are only off by a bit”)
I learned this quote from Tony Barr, designer and developer of SAS (the Statistical […]
Power of Logic Operators: a trick
Suppose you should group people based on their ages as follows:
ID
Age
agegrp
001
1
1
002
4
2
003
5
2
004
5
2
005
2
1
006
4
2
007
5
2
008
2
1
009
9
3
010
8
3
and the rules:
age<4, group 1
4<=age<6, group 2
6<=age<10, group 3
It is a very simple question and you could use the if/else statement without thinking:
data age;
input ID $ age;
datalines;
001 1
002 4
003 5
004 5
005 2
006 4
007 5
008 2
009 9
010 8
;
data age1;
set age;
if age<4 then agegrp=1;
else if […]
Logics in mathematics and in daily life: a statistical programming example
Refresh some basic logical propositions (or statements):
implication: if P then Q (P—>Q)
inverse: if not P then not Q (-P—>-Q)
converse: if Q then P (Q—>P)
contrapositive: if not Q then not P (-Q—>-P)
contradition: if P then not Q (P—>-Q)
Mathematically or logically speaking, if the implication statement holds, then the contrapositive holds, but the inverse does not hold, […]