MAT013 Coursework

Deadline: May 4, 2017

Instructions

The outputs of this coursework will be:

A written report in doc-, pdf- or html-format describing your code (SAS and R) and screenshots with comments to be handed in to Lauren Trundle.
A file containing the required SAS code. Name this file STUDENTNUMBER-SAS-lastname (eg. 123456-SAS-Evans) and email it to Lauren Trundle with MAT013 as the subject. Note that all operations needed to complete the coursework should be included in the SAS code.
A file containing the required R code. Name this file STUDENTNUMBER-R-lastname (eg. 123456-R-Evans) and email it to Lauren Trundle with MAT013 as the subject. Note that all operations needed to complete the coursework should be included in the R code.

Coursework

Consider the data set two_thirds.csv which contains two columns of numerical data. These represent 1st and 2nd guesses for the game: “Two Thirds of the Average”.

The rules of which are explained here: vknight.org/two_thirds_of_the_average_game/two_thirds_of_average_game_fill_in_sheet.pdf

Using R:
1. Draw two histograms: one for each set of guesses.
2. Identify the winning guess for each set of guesses.
Attempt to do this in a generic way (so that your code would work for a different data set).

[15]
A perfect number is a natural number that is equal to the sum of its divisors (excluding itself). For example $1,2,4,7$ and $14$ divide $28$ and $28=1+2+4+7+14$.

Write code in SAS that allows one to write to a csv file a data set with all natural numbers less than a given parameter $N$ as well as a boolean variable indicating if the number is perfect or not. For example, for $N=6$ the csv file would contain the following:
```
 1, False
 2, False
 3, False
 4, False
 5, False
 6, True
```
[30]
Using R, create a function which has two arguments and returns the product of two matrices without using the operator %*%. To compute the product, use the nested for cycles and functions nrow(..), ncol(..). Generate 2 random matrices and verify the output of the function by comparing with the operator %*%.
[10]
Consider the data set jokes.csv which contains jokes that have been ranked for the Edinburgh Fringe Festival for the years 2009-2015.

Using R:
1. Identify the effect of joke length on the performance of a joke.
2. Identify if authors who have repeated entries seem to do better than authors who do not.
(Note that this question is not asking for sophisticated sentiment analysis.)

[25]
Suppose that we want to compute the integral
$I=\int_{-\infty}^{\infty}f(x)p(x)dx,$
where $p(x)$ is the density of standard normal distribution. Consider the sum
$S_N=1/N\sum_{i=1}^N f(z_i),$
where $z_i,i=1,...,N,$ are independent identically distributed random variables with the standard normal distribution. By the Central Limit Theorem, we have $S_N \to I ~~as ~~N\to\infty,$
Thus, $S_N$ is an estimator of $I$.
Consider the function $f(x)=\cos(x)/(1+x^2)$. Using R, write a function with argument $N$ which returns $S_N$ . Write a file with 50 evaluations of this function for $N=1000$. What can you say statistically about $I$?

[20]