Standard Deviation

I love the potential oxymoron in this phrase.  I imagine two gossips talking about another’s peccadillo, and being interrupted by a third declaring ‘oh, that’s rather a dull, standard, deviation’.

Statistically it’s a concept which it is easy to explain, but I find hard to understand.  It’s a formula which attempts to describe how spread out the data is in a set of data, in other words, on average how distant is each data point from the average of the whole data set.

Or, in other words it attempts to answer the question “how spread out is the data?”

In the video above I can follow this fairly well until he does the difference between x and ‘x bar’.  What he’s referring to here is a calculation which gives you the difference between each data point and the mean of the whole data point.  You square these, I think, so that you end up with a positive number.  This seems to be the case because the final step is to find the square root, so you’re sort of taking the square out again (sort of).

What does the number tell you? I think that it tells you very little on its own –  the SD means little unless you know the mean of the data set, beyond the general rule that the closer the number is to zero the narrower the spread of results.  If the mean is 50 and the SD is 10 this would suggest a wider spread than if the mean is 100 and the SD is 10.

 

Teeth  

IMG_9457At the dentist a couple of weeks ago, whilst he tugged and levered a stoutly resisting molar, I wondered what they see when looking inside a mouth.  My dentist was sweating slightly, because pulling on the tooth had taken half an hour, and got us nowhere.  He suggested we cut it into quarters and do one bit at a time.

He got some sort of dental hacksaw, and go to work, muttering in grey, too near for focus, about the ‘strange morphology’ of my tooth.

To take my mind away, I wondered whether he considered the historical record that mouths present – my mouth in particular.  Was the decay a tell tale sign of the sweets and pepsi phase I went through in the late eighties?  Are there any traces left of Ed, university champion roll-up smoker and drinker of gallons of tea (being no good at drinking alcohol)?

I wondered if the few white fillings purchased in flush times before children, now coffee stained, are testimonials of my fall in the world, or whether it was just age, time passing, creeping entropy that he saw described in my ivories.

Forest Pasta

I made this yesterday. It’s probably obvious, but I record it here in case I forget what I put in and when I made it. it serves 4-6 normal people and 3-4 Podesta people.

Bacon / Lardons (not that many actually)
Onions (one or two) diced or sliced depending on how you like it.
Pellegrino Marsala
Whole box of mushrooms, sliced
Knob of butter
Dried Basil
Dried Oregano
Dried Thyme
Goats cheese ‘log’
Pasta – as much as you need to feed them all.

Put the bacon in a heavy frying pan and cook it till it gives off its fat. Then put in the onion, and cook it till it starts to brown a bit.

Start to cook the Pasta now.

Use the marsala to deglaze the pan and then add the mushrooms and a bit of butter. Add the herbs then cook the lot till the mushrooms are well done.

Put in about a third of the cheese in with the mushrooms and bacon and then put the cooked pasta in this pan. Mix it all up.

Serve up and use the rest of the cheese to crumble over the top of each portion.

Public Transport

”Anybody can use Public Transport, Sweetie!”

21550506194_cd6e60172d_qI’ve a new job, which is a blissful 3.7 miles away. This means that when the mood takes me I can cycle. If it’s raining or if I’m feeling lazy then I can get the bus. After years of driving to workplaces I’m back on public transport and rediscovering the opportunities for reading, observation and contemplation that bus travel brings. If the bus is late I get a few more pages of my book read. On the bus I can look at the scenery (it helps if you live in north Leeds where there are some great views), or observe the extremely varied fellow-passengers. I like the noise of engine and the ding of the bell, and the way that kids LOVE travelling on buses.

In just two short months I’ve seen loads of things that restore my faith in humanity.  People say ‘after you’, or they get up from the priority seats when it looks like someone else needs them more.  An elderly lady looked after another who was a bit confused and kept saying ‘I’m gonna be sick’.  She spoke softly, and let her know which stop she should be getting off at.   That same lady, who’s a regular, has a walking frame, and I’ve seen a couple of people help her on and off the bus with it.

I only have to get in my car when I’m working in Bradford, and I think I might investigate the train and shanks’ pony for this, given how much more relaxing it is when someone else is doing the driving.

the harried autodidact

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