Statistics and Statistical Programming (Winter 2017)/R lecture outline: Week 3: Difference between revisions

Latest revision as of 19:38, 25 January 2017

Review of material from class[edit]

loading data:
- load() versus read.csv()
- when things don't coopreate...
- library(foreign)
defining functions
- syntax for defining functions: show the my.mean function
- calling functions (your own or others) with apply(), lapply(), sapply()
stuff related to distributions
- rep()
- seq()
- sample(); and sampling into data.frames

Online only[edit]

dates with POSIXct(). dates will almost always be given to you as characters, and you need to parse them
tapply(), and putting things back into data.frames
merge()

@@ Line 1: / Line 1: @@
-* problems folks ran into:
+== Review of material from class ==
-** loading data:
-*** load() versus read.csv()
+* loading data:
-*** when things don't coopreate...
+** load() versus read.csv()
-*** library(foreign)
+** when things don't coopreate...
-* other things that have come up
+** library(foreign)
-** dates with POSIXct(). dates will almost always be given to you as characters, and you need to parse them
+* defining functions
-** ordered() — really just a type of factor for ordinal data
+** syntax for defining functions: show the my.mean function
-* new things that are going to be very useful
+** calling functions (your own or others) with apply(), lapply(), sapply()
-** defining functions
-** merge()
-* looping
-** apply(), lapply(), sapply()
-** for looping
 * stuff related to distributions
 ** rep()
 ** seq()
-** sample()
+** sample(); and sampling into data.frames
-** distribution functions: lets focus on *unif(): the key is on page 222 of Verzani
-*** The “d” functions return the p.d.f. of the distribution
+== Online only ==
-**** dunif(x=1, min=0, max=3) # 1/3 of the area is the to the left 1
-*** The “p” functions return the c.d.f. of the distribution.
+* dates with POSIXct(). dates will almost always be given to you as characters, and you need to parse them
-**** dunif(q=2, min=0, max=3) #1/(b-a) is 2/3
+* tapply(), and putting things back into data.frames
-*** The “q” functions return the quantiles.
+* merge()
-**** qunif(p=0.5, min=0, max=3) # half way between 0 and 3
-*** The “r” functions return random samples from a distribution.
-**** runif(n=1, min=0, max=3) # a random value in [0,3]