Editing Statistics and Statistical Programming (Winter 2017)/R lecture outline: Week 3
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* problems folks ran into: | |||
** loading data: | |||
* loading data: | *** load() versus read.csv() | ||
** load() versus read.csv() | *** when things don't coopreate... | ||
** when things don't coopreate... | *** library(foreign) | ||
** library(foreign) | * other things that have come up | ||
* | ** dates with POSIXct(). dates will almost always be given to you as characters, and you need to parse them | ||
** | ** ordered() — really just a type of factor for ordinal data | ||
** | * new things that are going to be very useful | ||
** defining functions | |||
** merge() | |||
* looping | |||
** apply(), lapply(), sapply() | |||
** for looping | |||
* stuff related to distributions | * stuff related to distributions | ||
** rep() | ** rep() | ||
** seq() | ** seq() | ||
** sample() | ** sample() | ||
** 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 | ||
**** 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. | ||
* | **** dunif(q=2, min=0, max=3) #1/(b-a) is 2/3 | ||
* | *** The “q” functions return the quantiles. | ||
**** 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] | |||
