DA

Introduction

This is an R Markdown document. 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 a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

favstats(fastest~seat,data=m111survey)

##       seat min    Q1 median  Q3 max     mean       sd  n missing
## 1  1_front  60 90.00    100 119 130 102.2593 19.15241 27       0
## 2 2_middle  80 90.00    100 110 143 102.9688 15.34230 32       0
## 3   3_back  90 97.25    115 130 190 121.9167 30.09820 12       0

You can also embed plots, for example:

bwplot(fastest~seat,data=m111survey,
       xlab="Seating Preference",
       yalb="Fastest Speed Driven (mph)",
       main="Speed and Seating at GC")

Practice

use R to add 2 and 2, by inserting the appropriate command inside the code chunk below.

2+2

## [1] 4

Dolphin Communication: Your Coin Flips

How many heads did you get? 5

Dolphins Again: Your App Simulations

How many times did you simulate? 200,000

What percentage of the time did you get 15 or more heads? .03

Suppose Buzz is just guessing: about what’s the chance that he would get 15 or more correct? about 1/3000 tries

Based on your results, do you think we have strong evidence that Buzz and Doris can communicate? Yes.

R as a Calculator

Practice Part a

We can use R to find 2+7-3*5. Run the code chunk below to see if it works:

2+7-3*5

## [1] -6

You should get -6.

Pratice Part b

Next, insert write into the following the code needed to (25.5-20.2)/3:

Practice Part c

Next, insert your own code chunk below and write into it the code needed to produce the 12 squared plus 10 squared.

Practice Part d

Finally, insert your own code chunk and put write into it one line of code that does all of the following:

• squares 3.1, then divides it by 25
• squares 5.2, then divides it by 36
• adds the previous two results together
• then takes the square root of the result

Data Frames

Practice Part 1

Run the following code chunk to learn about m111survey:

data(m111survey)
View(m111survey)
help(m111survey)

How many students took part in this survey?

Practice Part b

Is fastest a numerical variable or a factor variable?

Is seat a numerical variable or a factor variable?

Practice Part c

How many students did not answer the question about their ideal height?

Making Lists with R

Practice Part a

In the following code chunk, insert the code needed to make a list of 100 fives.

Practice Part b

In the following code chunk, insert the code needed to make a list of all the numbers from 100 to 220, going up in steps of 10.