Psychology AS survey July 2013

Please can you take a few minutes to fill out the following survey:

http://www.surveymonkey.com/s/VPSQZ86

Thanks - your responses will help students in future years

Cheney psychology conference 2013

A reminder about next week's psychology conference. You need to have gathered all your data and finished your poster by 8.30 on Thursday morning (18th). On Thursday come to R23 at 8.30 as normal and we will walk over to the community hall together at around 9 and set up. 

Statistics Resources and Mini-Experiments to write up

Here is the 'using the sign test' sheet which was the first statistics homework I set.

Here is the 'choosing a statistical test' flowchart which you need to learn (for your statistics test on Tuesday 16th July).

Here is the 'significant or not significant?' sheet which we had a go at in the lesson today.

Here is the 'four more tests to do' sheet which forms part of your homework for the next Tuesday.

You also need to produce a short write-up for each of the experiments that we have done. Your write up should look like a couple of sides (handwritten) or one side typed and include the following:

• Title and date
• Aim of the investigation
• Null and alternative hypotheses (operationalised)
• Procedure – very brief outline (3-5 lines)
• Results table
• Justification of statistical test
• Level of significance chosen
• Working for test
• Explanation of level of significance reached and conclusion

The questions we have addressed in our recent lessons are:

Is it easier to locate a face in a crowd with eyes looking at you than with eyes looking to the side?

Is there a difference between the verbal reasoning skills of male and female students?

Are your judgements of how hard you have worked and your intelligence related to how well you think you have done in your exams?

Are women more likely than men to mention their own looks in a personal ad?

Here are the results for these, with calculations still to complete.

Statistics - Part 2

Yesterday we spent some time looking at nominal, ordinal, interval and ratio levels of measurement. The key thing here is for you to be able to spot when the data is ordinal or only nominal.

We looked at the Wilcoxon Signed Ranks test - this is used to decide if scores in a repeated measures design experiment are significantly different. The data needs to be at least ordinal, because you have to rank the differences from smallest to largest, then add up the ranks of the positive differences and the ranks of the negative differences. If the smaller of these is less than the critical value (from the table) then the result is significant - in other words only a few results went 'the wrong way' and these only by a bit.

For Monday, make sure you have completed the Using the Sign Test sheet.

Also - gather some experimental data on open and closed passes. An open pass is when a person squeezes past someone else with their front to them - a closed pass is when they put their back to the other person. Create a tally chart for male and female passes and record the number of open and closed ones you observe for each.

Also have a go at the Mann-Witney U Test on the three-page sheet (on which you completed the Sign Test and Wilcoxon). The tricky bit here is that you have to rank the actual scores (NOT the differences between the scores - as this is and independent groups design the scores aren't actually in pairs), and you have to do this AS ONE GROUP meaning that you should get up to 20.

Statistics lesson 1 - the sign test

Here is the presentation from today's lesson.

The key idea to take from this is that when we have quantitative data, we can use a statistical test to see how likely the results were to have happened simply by chance. This is the same thing as the chance of the null hypothesis being true given what happened in our experiment.

Scientists choose a 'level of significance' before starting an experiment. This is the probability of the results happening by chance alone below which they will reject the null hypothesis, and conclude that their alternative hypothesis is true. In psychology 5% (or p<0.05) is usually chosen - this means that if there is a less than 5% chance of the results happening by chance alone then the result is considered to be significant - down to whatever the effect being investigated is.

The 5% level gives a balance between the two types of error - false positives (Type I) and false negatives (Type II). Sometimes the 10% level is used - this means there is a greater chance of a false positive (saying you have found something when you haven't) but you are less likely to have a false negative (saying nothing was going on when really it was). When it's important to avoid a false positive a lower level e.g. 1% or 0.1% is used - but this means that a false negative is more likely.

Here is the 'using the sign test' homework sheet - for Thursday, along with the sign test section on the other sheet I gave out.

Final Unit 2 revision...

Tuesday at 12.20pm in R23!

Preparation for Mock - 11.20am on Tuesday 30th April

Here is a slightly edited version of the examiner's report for the paper which you will sit on Tuesday.

It contains lots of useful advice in general about exam technique for AS psychology (and, indeed, other subjects), and lots that is specific to this exam. I am allowing you to work out what the questions are on, in the hope that you will read this document carefully and realise how useful it is!

You can download examiners' comments for all past papers for all subjects from the websites of all the exam boards. It's really useful to read these, especially just before or just after you have a go at a past paper.

I am offering a revision session on Monday after school in R23, with the aim of going through the June 2012 Unit 2 paper. I suggest you do this over the weekend, mark it yourself using the mark scheme, and bring it along to go through it and discuss issues it throws up. Here is the examiner's report for this paper.

If you haven't already, email me your revision card - see post below if you have forgotten your topic!