R Language

4 and a half myths about beta in finance

February 8, 2011 | Pat

Much of what has been said and thought about beta in finance is untrue. Myth 1: beta is about volatility This myth is pervasive. Beta is associated with the stock’s volatility but there is more involved.  Beta is the ratio of the volatility of the stock to the volatility of ... [Read more...]

Review of “R Graphs Cookbook” by Hrishi Mittal

January 24, 2011 | Pat

Executive summary: Extremely useful for new users, informative to even quite seasoned users. Refereeing Once upon a time a publisher asked if I would referee a book (unspecified) about R.  In an instance that can only be described as psychotic I said yes.  That bit of insanity turned out to ...
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Paying interest and the number e

January 24, 2011 | Pat

Suppose I borrow a dollar from you and I’ll pay you 100% interest at the end of the year.  How much money will you have then? $1 * (1 + 1) = $2 What happens if instead the interest is calculated as  50% twice in the year? $1 * (1.5 * 1.5) = $2.25 After … Continue reading →
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Interesting volatility measurement, part 2

January 21, 2011 | Dzidorius Martinaitis

A few weeks ago I have mentioned about an interesting volatility prediction. It is based on two periods of historical volatility (standard deviation). The remaining question was – does it really works? I could not give the answer, because I didn’t have VIX futures data at that time. Later on, ...
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Normal market accidents

January 17, 2011 | Pat

We think of accidents as abnormal events, but there is “normal accident” theory.  We don’t think of accidents happening in markets, but they do.  That’s why it’s called a market crash. For normal accidents to come into play, two conditions need to hold: the system is complex ...
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The number 1 novice quant mistake

January 12, 2011 | Pat

It is ever so easy to make blunders when doing quantitative finance.  Very popular with novices is to analyze prices rather than returns. Regression on the prices When you want returns, you should understand log returns versus simple returns. Here we will be randomly generating our “returns” (with R) and ...
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Seasonal pair trading

January 10, 2011 | Dzidorius Martinaitis

quanttrader.info is a good quantitative repository, where I found an idea about seasonal spreads play. The idea of seasonal pair trading differs from pairs trading in a way, that it doesn’t try to find deviation from the spread’s mean, but it looks at seasonal spread patterns. In ...
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Some market predictions

January 6, 2011 | Pat

We look at a few forecasts for the year 2011 that we’ve run across, and compare them with the prediction distributions presented in Revised market prediction distributions. FTSE 100 There is a “range forecast” on an Interactive Investor page of 5350 to 6565.  It isn’t clear (to me at least) what this ...
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Customizing the Theme of Your R HTML Help

January 4, 2011 | Yihui Xie

R’s default theme of the HTML help pages is too plain for me to read, but we can easily modify the theme, which is essentially a CSS file. You can find the file under: file.path(R.home('doc'), 'html', 'R.css') Simply replace this file with my version: ...
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Revised market prediction distributions

January 4, 2011 | Pat

This provides revised plots of the prediction distributions published yesterday.  The previous plots of prediction distributions should be ignored — they are not doing as advertised. We show the prediction distribution of levels of several equity indices (plus oil price) at the end of 2011 assuming nothing happens.  That is, we’ve ...
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Creating prediction distributions

January 4, 2011 | Pat

Here we give details and code for the prediction distributions exhibited in yesterday’s blog post Tis the season to predict. Eight years of returns The equity indices use daily closing levels from the start of 2003.  This data comes from Yahoo. A roughly equivalent technique of selecting the last 2000 daily ...
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Blog year 2010 in review

December 30, 2010 | Pat

The blog year started in August and consists of 30-something posts.  Here is a summary. Quant concepts backtesting: Backtesting — almost wordless cointegration: American TV does cointegration efficient frontier: Anomalies meet volatility implied alpha: Implied alpha — almost wordless portfolio theory: Ancient portfolio theory random walk: The tightrope of the random walk ...
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High readings of VIX index during 2 days

December 28, 2010 | Dzidorius Martinaitis

During last two sessions (December 23th and 27th), VIX index posted returns (close to close) above 6 %. My question is – what return can we expect next day after such event? As you can see from the graph above, expected return is positive. During 1995-2010 were 53 such events and mean return was 1.02 % [...]
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The tightrope of the random walk

December 27, 2010 | Pat

We’re really interested in markets, but we’ll start with a series of coin tosses.  If the coin lands heads, then we go up one; if it lands tails, we go down one. Figure 1: A coin toss path.Figure 1 is the result of one thousand coin flips.  It is ...
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Some quibbles about “The R Book” by Michael Crawley

December 13, 2010 | Pat

A friend recently bought The R Book and I said I would tell him of problems that I’ve noticed with it.  You can eavesdrop. Page 4 The word “library” is used instead of “package”.  This (common)  error substantially raises the blood pressure of some people — probably to an unwarranted extent. ...
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Interesting volatility measurement

December 10, 2010 | kafka

Long time ago I stumbled across interesting volatility measurement at quantifiableedges.blogspot.com. The idea is following: take 3-day historical volatility of S&P 500 index and divide that by 10-day historical volatility. Then mark all points which are less that 0.25 and measure the volatility of 3 following days. On average, the ... [Read more...]

3 weak days in a row

December 6, 2010 | kafka

Recently, Trading the odds posted one of many flavors of mean reverting strategies and I decided to get my hands dirty by writing R code and testing it. You can find full description of the strategy by following latter link above. Long story short – if SPY shows lower open, high ... [Read more...]

Bear hunting

December 6, 2010 | Pat

When were there bear and bull markets in US stocks since 1950? Smoothing While we’d really like to estimate the expected return at each point in time, finding bear markets is ambitious enough.  The plan starts by smoothing the daily returns through time, as in Figure 1. Figure 1: Smoothed returns with ... [Read more...]

Joy of Stats coming soon

November 29, 2010 | Pat

The Joy of Stats really is a joy.  It will be shown on BBC4, apparently scheduled for December 7.  (That date comes from Hans Rosling on twitter, I haven’t found scheduling evidence at the BBC.) I saw its debut at the Royal Statistical Society on World Statistics Day. Here is ...
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Yet another inferno

November 26, 2010 | Pat

Many from the R world will know The R Inferno. Abstract: If you are using R and you think you’re in hell, this is a map for you. A newly minted inferno is The 9 circles of scientific hell. Most amusing to me is Circle 4: p-value fishing, the punishment of ...
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