---
title: "Intro to Rmarkdown and home exercises"
author: "Your Name"
date: "4.8.2023"
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

### R Markdown

This is an R Markdown document. Open the .Rmd version of it in Rstudio. 
Markdown is a simple formatting syntax for authoring 
HTML, PDF, and MS Word documents. For more details on using 
R Markdown see <http://rmarkdown.rstudio.com>.

When you click the **Knit** button in Rstudio icon bar a html/pdf/word document will be 
generated that includes both the content as well as the output of any 
embedded R code chunks within the document. 
You can embed an R code chunk like this:
```{r}
x = 1:5
sqrt(x) #compute square root of 1,2,...5.
```

You can choose the output format (html/pdf/word) from the downward arrow 
on the right hand side of the `Knit` button.

If your `Knit` button doesn't have the PDF option available, 
you should follow the instructions at
<https://yihui.org/tinytex/>
to install the `tinytex` package. 
Namely, run in the R console 
the following commands (which are not run automatically here because
we have set `eval = FALSE` in the R code block below)
```{r, eval = FALSE}
install.packages('tinytex',repos = "https://cloud.r-project.org")
tinytex::install_tinytex()
# to uninstall TinyTeX, run tinytex::uninstall_tinytex() 
```

Home exercises are given in Rmd files (also PDF is given).
You can do the exercises using R markdown by directly writing your answers
below each question (remember to use R chunk for code in order that Rstudio knows
to interpret it as code and run it in R). 
Return your solutions as a PDF or HTML 
file by saving from R markdown (option arrow on the right hand side of **Knit** button). 
If you `Knit` to a Word file, then save the result in Word as PDF before returning the document.

Note that your solutions must
contain both the R code and the output from R when 
the code was run, including the plots that were asked to be drawn. 

If you are not able to get Rstudio to `Knit` Rmarkdown file, you can
write your solution code in a new R script file 
(Choose File -> New File -> R script).
Then you should run
the commands on the console and copy the relevant output to your solution file (also figures),
which may be a text file of any type (such as MS Word), and save the final document as PDF.
But this is not the recommended option because copy-paste is complicated and error prone,
and you won't learn to use Rmarkdown for your future projects.


#### Toy set of exercises

Write your name at the beginning of this file as "author:".

Write your answers below each question using chunks for R commands.
After every step, you can `Knit` to HTML and see that everything looks good.
Once you are ready with everything, 
try to create a PDF and check that also it looks good.
Solutions to 2 & 3 are given at the bottom of this document.

(1) Assign value 2 to variable `x` and compute `x + 3`.

```{r}
#Your answer goes here
x = 2
x + 3
```


(2) Suppose that we have checked the month of birth for 
$N = 5000$ MS-disease patients
and observed that $A = 485$ of them were born in April.
Compute how large proportion of the patients were born in April. 
(A code block is made ready for you below, just put there your R commands.)

```{r}
#Your answer goes here
```


(3) Compute the mean and the standard deviation of the following 
5 values: 4, 92, 11, -5, -12.
(Start by making a code block for your R commands, for example, by copying a block 
from above or by choosing **R** from `+C` button in the bar above this editor.)



#### Answers 2-3.


Answer (2).
```{r}
N = 5000
A = 485
A / N
```

Answer (3).
```{r}
x = c(4, 92, 11, -5, -12)
mean(x)
sd(x)
```