My road to rock stardom had taken a bit of a knock with my unexpected entry to an all-boys' grammar school (rock bands and grammar schools really didn't go together). I needed to be inspired and I turned to the masters: Iron Maiden. I first heard Iron Maiden at the age of 11 when a friend of mine lent me Piece of Mind and told me to listen to 'The Trooper'. It was, to put it mildly, an epiphany. I became their smallest (I was 11) biggest fan and started to obsess about them in the unhealthiest way possible. I started stalking the man who ran their fan club with letters, and, bless him, he replied. Eventually this stalking paid off and he arranged for me to go backstage when they played the Hammersmith Odeon in London (now the Hammersmith Apollo) on 5 November 1986 (Somewhere on Tour in case you're interested). Not only was it the first time that I had seen them live, but I got to meet them too. It's hard to put into words how bladder-splittingly exciting that night was. I was so utterly awe-struck that I managed to say precisely no words to them. Soon to become a theme in my life, a social situation had provoked me to make an utter fool of myself.1
When it was over I was in no doubt that this was the best day of my life. In fact, I thought, I should just kill myself there and then because nothing would ever be as good as that again.2 This may be true, but I have subsequently had many other very nice experiences, so who is to say that they were not better? I could compare experiences to see which one is the best, but there is an important confound: my age. At the age of 13, meeting Iron Maiden was bowel-weakeningly exciting, but adulthood (sadly) dulls your capacity for this kind of unqualified joy of life. Therefore, to really see which experience was best, I would have to take account of the variance in enjoyment that is attributable to my age at the time. This will give me a purer measure of how much variance in my enjoyment is attributable to the event itself. This chapter describes analysis of covariance, which extends the basic idea of ANOVA from the previous chapter to situations when we want to factor in other variables that influence the outcome variable.
1 In my teens I stalked many bands and Iron Maiden are by far the nicest of the bands I've met.
2 Apart from my wedding day, as it turned out.