R/C2/Introduction-to-basics-of-R/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on basics of R.
00:06	In this tutorial, we hope to provide a feel for R and Rstudio
00:11	How can R be used as a calculator?
00:14	How to use built-in functions like sin and log?
00:17	Introduction to vector operations
00:19	Introduction to plotting
00:21	Taking help in RStudio and
00:24	Where to get more information on R and Rstudio
00:28	To understand this tutorial, one needs to know elementary maths.
00:32	For example, log, sine and plotting
00:35	Please locate this tutorial on our website, spoken tutorial dot org
00:40	We provide many useful supplementary material in this page
00:44	No programming background is required, however, to understand this tutorial
00:50	I am using version 3 of R,Using RStudio 0.97
00:56	R and RStudio work on web browsers also
01:00	Hence, these are easily accessible from every operating system, including Aakash
01:07	Let us continue with system requirements.
01:09	For this tutorial, I am using Mac OS X 10.7.4
01:14	But the usage is similar in Linux and Windows as well
01:18	Let us give a quick introduction to R.
01:21	R is an outstanding software for general computations
01:24	It is especially suitable for statistical computing
01:27	It is an alternative to SPSS
01:30	It is a free and open source software
01:32	It can be downloaded from c ran dot r dash project dot org
01:39	Let us now give a quick introduction to Rstudio
01:42	RStudio is a friendly front-end to R
01:45	It is a free and open source software
01:48	It can be downloaded from rstudio dot com
01:51	A two minute video by the RStudio team is available here.
02:01	Let me return to the slides.
02:05	RStudio also runs on a web browser.
02:09	Here is a screenshot of R and RStudio on a web server, accessed from Aakash
02:15	Let us do a practice session on R, using Rstudio
02:21	You now see RStudio on the screen.
02:24	I have shrunk its size quite a bit, to fit into a small screen.
02:29	Please use a size you are comfortable with.
02:32	I have also enlarged the font size, so that the recording is clear.
02:36	You do this on Windows and Linux, by pressing control and + keys together.
02:41	For this tutorial, I want to maximise the size of the console of Rstudio.
02:48	I do this by pressing the maximise button in the console window.
02:54	I also maximise the right lower window of RStudio in a similar manner.
03:02	Let me begin multiplying two numbers two point one and five.
03:12	R gives the answer in black as ten point five.
03:16	I want to divide this by three.
03:18	I will recall the previous command by clicking the up arrow.
03:22	What I typed earlier, namely two point one into five appears.
03:26	I will divide this by three to get the answer three point five.
03:31	I can add two numbers.
03:35	I can store the result in a variable using the assignment operator.
03:42	Less than symbol followed by hyphen.
03:48	One can also use an equal sign.
03:53	If I want to see what is in a variable, I just type the variable name.
03:59	In this case, I type a and see that it has five.
04:03	I will subtract zero point one six from a.
04:11	I will raise it to the power of zero point 5.
04:15	Remember, I have to put a minus zero point one six within brackets, to get the correct answer.
04:26	We get two point two, as expected.
04:29	Using the left and right arrows, I moved the cursor back and forth within a command.
04:35	I can also carry out the same calculation using the function call, square root.
04:48	I will find the value of e by using the function call, exp.
04:55	You may have noticed, the moment I open a bracket, R automatically closes it.
05:01	This eliminates errors due to unmatched brackets. So, we see the value of e above.
05:08	I can find the natural logarithm of e with the help of the log function.
05:18	The value is one, as expected
05:22	How do we find the log to the base ten?
05:25	Use the command log10.
05:30	Ten to the power five.
05:36	This gives the answer as five, as expected.
05:40	What happens if I forget the ten in log10?
05:48	We get a different answer.
05:50	It is easy to verify that this answer is correct for natural logarithm.
05:54	Can you please suggest a method to verify this?
05:57	There is another way to find the logarithm to the base of 10.
06:04	Give the base as the second parameter, as I do here.
06:13	We get five, as expected.
06:16	It is easy to create vectors in R.
06:19	z = s e q -1 comma 2 comma 0:5
06:29	This creates a vector starting at minus one, going up to two, in increments of point five s e q denotes sequence.
06:44	Let us see the value of z.
06:48	We will see other ways to create vectors in another tutorial.
06:53	We can calculate the length of the vector z using the command length:
07:01	We get the result seven, as expected.
07:07	We will now discuss pi.
07:09	The value of pi, is stored in the variable pi, p i, which we can see now.
07:16	Let us create a vector x to start from minus two pi, go up to plus two pi, in increments of one.
07:30	Please remember to put the multiply sign.
07:34	Let us see what x contains
07:38	Let us find the sine of this vector using sin and store it in y.
07:51	We can work directly with vectors in R, as we did above.
07:56	Let us see what y contains.
08:00	Let us plot sin(x) versus x, with type=L argument added.
08:12	Note that x comes first and then y.
08:17	This plot starts from zero as expected, because sin of minus two pi is zero.
08:24	The plot is not smooth, as there are not many points.
08:28	Let us now get more points by lowering the increment number to point one.
08:41	What happens if I try to plot without recalculating y?
08:46	R will complain that the lengths are unequal.
08:52	You should pause the video and confirm that the lengths are unequal.
08:57	Let me recalculate y.
09:00	Let me re-plot this curve.
09:05	You can see that the plot is smoother now.
09:08	Please pause the video now and look at the values stored in x and y.
09:13	Please confirm that these values are as per expectation.
09:18	We see the lengths of x and y to be 126.
09:28	You should verify that these lengths are correct.
09:31	You should also display the values of x and y and verify.
09:35	If we drop the type parameter in the previous command, we get a plot with points.
09:45	Let us press the help button in the right hand side window.
09:49	Let us type plot next to the lens symbol and hit return.
09:58	Let us scroll.
10:00	One can see different choices for the type parameter.
10:04	We have come to the end of this tutorial.
10:08	Let us see a few low cost books on R.
10:17	In this tutorial we learnt about, a few elementary operations
10:22	Introduction to plotting
10:24	Introduction to help
10:26	URLs and books on R and Rstudio
10:30	We now suggest an assignment
10:32	Find answers to log2 (2^5) and log (e^2)
10:39	Please explain your answers
10:41	Explore the Help tab in RStudio: Change the labels, title, etc.
10:47	Hint: try the plot command with x l a b argument
10:53	Copy paste a few examples provided in Help and see what they do
10:58	This video summarises the Spoken Tutorial project.
11:02	If you do not have good bandwidth, you may download and watch it.
11:06	We conduct workshops using Spoken Tutorials.
11:09	Give Certificates.
11:12	Please contact us.
11:15	The Spoken Tutorial project is funded by MHRD, Gov. of India
11:22	Thanks for joining, goodbye

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