Wednesday, September 30, 2015

Recommended statistics book

Hopefully my silence here over the past two weeks can be interpreted as being due to a period of hard work interspersed with holidays in which I have done little. That description corresponds quite well to the truth.

Over the past few days, I've been working once again on the statistical analysis of the interim data collected during the pilot study of my doctorate. This follows an interchange with my mentor whom at first I thought was misunderstanding me; it turns out that I was misunderstanding him. I should try to remember that whenever he writes something which seems to be wrong, he is writing from a position of knowledge and so I should try and see from his point of view what is wrong.

It appears that I was labouring under a misunderstanding regarding some of the variables, and I've been working on redefining them. To recap, a variable can be one of four types: interval (eg age, IQ, years of employment), ordinal (data which can be ranked, but the gaps between each value are not constant), nominal (name only, eg religion, department) and dichotomous (two values only, eg gender).

Only data from interval variables can be aggregated; my mistake was trying to aggregate ordinal data. Having improved my understanding, I can now see how the misunderstanding arose: ordinal data can participate in multiple regression analysis (where each option is assigned a dummy value), but one can't aggregate those dummy values from more than one question.

So whereas before I had one variable called 'Training', composed of the aggregate value of three questions, I now have three variables entitled 'frequency of training', 'type of training' and 'quality of training'. These variables are compared to the dependent variable (use of spreadsheets with Priority data) by means of ANOVA and the F-test.

I can recommend the book "Statistics: a tool for social research" by Joseph F. Hailey as being both a good introduction and also a companion for the calculations required in my research. Unlike other books which I have read on the subject, Hailey begins with the four types of variables and notes which mathematical operations can be carried out of which type of variable. Of course, he carries on to show which analytical tools can be used on which type of variable. 

Although I had read about ANOVA elsewhere, the material had not been presented in the way which allowed me to make the connection with my data. In fact, there is a detailed ANOVA calculation in the 'Introduction to Business Research 3' course, but again this was presented in a slightly different way. IBR3 makes no mention whatsoever of the four variable types, which I think is a shame. I shall point this out to my mentor.

Sunday, September 13, 2015

New Year greetings

This evening is the Jewish New Year, so to all my readers - a happy and prosperous New Year! May this one be better than the last.

Let's climb into the time machine and set the dials for ... Rosh HaShana, 1975: 40 years ago. I spent the summer of 1975 on Kibbutz Bet Ha'emek, revisiting the glories of my gap year. I remember this as a lovely summer, which reinforced my decision to emigrate. Rosh HaShana is the only festival which is celebrated for two consecutive days. On both evenings, all the kibbutz ate at trestle tables set on the grass outside of the dining room.

I was flattered to be asked to participate in the pick-up band which played in the ceremony for the first night; I was playing bass guitar. As I recall, we played three songs. After the short ceremony, I stepped off stage to join my friends for the meal.

At some stage, I was asked whether I would work in the kitchen on the second holiday day. One might see this as being an out of line request, but it didn't bother me much: I would be going home shortly and I had one day off anyway. I spent the entire 8 hour shift cooking 800 pieces of chicken shnitzel for the kibbutz to eat on the lawn the second evening. I'm fairly confident that I didn't eat any myself.

Back into the time machine, I set the dials for Rosh HaShana, 1980: 35 years ago. I was in the middle of my army service then. Despite the efforts of the kibbutz secretary who told the army that I was required for the holiday celebrations on the kibbutz (who else could play the guitar?), I was short-listed for guard duty during the long holiday. Probably on the day, I was offered a choice: either stay on the base or travel to a moshav in the north of Israel and do guard duty there. I thought that the moshav would be more interesting than the base and so ignored the prime directive: never volunteer for anything in the army.

Along with two girls from my unit (who I didn't know; I spent my days in a laboratory which was situated outside of the actual unit, so I knew very few people there), I joined up with maybe thirty other soldiers. About eight of us were deposited at a place called Dishon, which is in the very far north of Israel, on the Lebanese border.

I had a horrible time: the guard duty itself was not too demanding, but the room in which we slept was infested with mosquitoes. To my great annoyance, none of the people living on the moshav took any interest in us; I thought that maybe we would be invited into someone's house to help celebrate the festival but we were ignored. One of the girls from my unit turned out to be a slag and spent several hours under the covers with one of the other soldiers. I don't remember now how or where we ate.

After arriving home, I discovered that - as usual - a surplus of soldiers had been asked to stay for guard duty and some had been released home. In other words, had I not volunteered to go to the north, I might well have spent the three days at home on the kibbutz. This was the cherry on the icing of a horrible few days (I can think of several alternatives to 'cherry', but none of them are polite).

Thursday, September 10, 2015

First cut

Whilst looking at the contents of my Kindle whilst connected to a computer, I discovered that it contained an unfamiliar title written by Peter Robinson, "First cut" (or maybe "The first cut"). It has happened that Robinson's books get republished under different titles, so I wasn't initially sure whether I had already read this book or whether it was new to me. It certainly was not stored in the Robinson collection on the Kindle which is why it had escaped my previous attention. 

The book contains alternate chapters from the point of view of two characters, Martha and Kirsten; later on, Martha disappears and is replaced by Susan. At first, the story seemed totally unfamiliar, but after a while I had a sense of deja vu, which was later authenticated by one character's name. I then realised that I was reading what was - or would later become - the back story in another Robinson book ("Friend of the devil"). 

Robinson himself writes in an afterword that the book was written after four Inspector Banks novels then cast aside and published only much later. This means that the book existed prior to "Friend of the devil". Of course, having finished "First Cut", I had to commence reading "Friend" in order to see how the stories connected. I have to admit that "Friend" is not one of my favourite Robinson novels and I've only read it two or three times; the inclusion of the backstory - what transpires to be the events of "First Cut" - always seemed to be a little forced; this time, I will be checking closely how the previous story is woven into the fabric of "Friend". 

"First cut" is a non-Banks story, telling events from the point of view of a victim. <Spoiler alert> Kirsten finishes her English degree then gets brutally attacked. Fortunately she is discovered before she dies of her wounds, but she initially remembers nothing of what happens. During the chapters from her POV, she undergoes a period of convalescence, both physical and mental. She sees a psychiatrist, and on the recommendation of the police, begins a series of treatment by hypnosis. At first, she remembers nothing but later manages to remember a face, an accent and a smell. Kirsten reads in the newspapers about six other girls who were attacked and killed in a very similar manner to which she was attacked. 

Enter Martha: her story is interwoven with that of Kirsten, but actually takes place a year later. What the reader does not know at first is that Martha *is* Kirsten: the face, accent and smell have lead her to a small Yorkshire town on the seaside, where she is certain her attacker is based. Her chapters tell how she tries to identify the man who attacked her; at first, her memory misleads her but later she finds the correct man. <End of spoiler alert> 

Robinson shows his background in English (he has a PhD!) very subtly at one point: Kirsten and her friend are discussing Thomas Hardy and how he uses metaphors to write about the erotic in Victorian times; there is a neat discussion of images used during a hanging. Those who don't pay attention to this discussion may miss that the name of the woman being hanged is Martha Browne. A bit later on, Kirsten reads "Jude the Obscure" ... and Martha Browne metamorphises into Susan Bridehead - the cousin and wife (at times) of the titular Jude. This tidbit seems to have escaped most reviewers. 

I found it very difficult to read "First cut" as a first time reader as I knew near enough what was going to happen. Of course, whenever I reread a book, I know what is going to happen, which allows me to concentrate on appreciating the writing without having to give so much attention to finding out what happens in the book. So, presumably, when I next read "First cut", I will be able to appreciate it more. I'll probably reread it after I finish "Friend of the devil".