lecture-04.Rmd

---
title: "Lecture 4"
---

### Group activity: 
given the homework and the R topics so far:
* what are your uncertainties and confusions?
* what have you discovered (or known from past experiences) outside what we have covered in class that you can share with others?

### Lecture handout: 
chp3-handout.pdf (continued from variance of linear combinations of random variables) and chp4-handout.pdf

### Lecture slides (w/ answers): 
chp3.pdf
chp4.pdf

### Textbook: 

Chapter 3: Probability, Chapter 4: Distributions of Random Variables

### R Topics:

```{r eval=FALSE}
length() #vs sum()
mean(), sd(), var()
which, subset
range
labels for graphs: plot(..., main="main title", sub="subtitle", xlab="x-label", ylab="y-label")
```


#### rmarkdown chunk parameters:
```
echo=TRUE (default)/FALSE: whether to show the code in the output document, or not 
eval=TRUE (default)/FALSE: whether to run the code or not , 
tidy=FALSE (default/TRUE: whether to tidy the code
results='markup' (default): 
results=hide: show only figures
results=asis: put the results into rmarkdown instead of the output document
results=hold: show the results after all the code in the block
```
for more info see https://github.com/rstudio/cheatsheets/raw/master/rmarkdown-2.0.pdf 
 
#### probability distribution functions
```
rnorm, dnorm, qnorm, pnorm
rgeom, dgeom, qgeom, pgeom
rbinom, dbinom, qbinom, pbinom
{r,d,q,p}nbinom
{r,d,q,p}pois
choose, lchoose
```