Key concepts Flashcards
the stroop experiment
two groups of people were timed at how long it took them to read a group of words (names of colours). in one condition, the words matched with the same colours as they read, but in the other, the word was a different colour to the font it was in. it took the second group longer to read all of the words.
baddeley and godden 1975
evluated ecological validity. 4 conditions; learning words on land and recalling words on land; learning words on land and recalling words underwater; learning words underwater and recalling underwater; learning underwater and recalling on land.
random sampling
the lottery method - select out of a hat
random number generator - number everyone. use the number generator to pick out your sample
consent forms
- random email for questions
- i confirm that i understand and agree that…
- tick boxes
- sign and date lines
coefficients
- always between -1 and +1
- bigger number = stronger relationship
- for a study to be reliable, it must be above +0.8
- stats test would be Spearman’s or Pearson’s
scattergram
you need:
- type of correlation (+ve/-ve/0)
- strength of correlation
- what it means in plain English
- any anomalies or change in direction?
descriptive statistics
measures of central tendency - mean, median, mode
measures of dispersion - standard deviation, range
interval - mean, standard deviation
ordinal - median, range
nominal - mode
graphs
table - numbers
bar charts - NOMINAL DATA. gaps between bars to show lack of continuity (different categories e.g. animals). frequency on the y-axis
scattergrams - CORRELATIONS (relationships). don’t join dots. axis labels can be either way round
histograms - bars touch each other. x -axis is equal sized intervals. y-axis is frequency. CONTINUOUS DATA
line graphs - CONTINUOUS DATA on the x-axis. y-axis is frequency. cross in the middle of the interval. join dots
distributions
normal distributions: classic symmetrical curve. mean median and mode are all in the midpoint. frequency on y-axis
MEDIAN IS ALWAYS MIDDLE
skewed distributions:
MODE IS ALWAYS TALLEST (NOT ALWAYS HIGHEST SCORE)
positive distributions: bunched towards the left. most scores on low end rather than high. mean is always furthest to the right, below mode and median.
negative distributions: bunched towards the right. most scores on the high end rather than the low. mean is always furthest to the left, below mode and median
research process
- find a topic your interested in
- create aim and hypothesis
- design study
- gain ethical approval
- do pilot study
- make refinements and conduct study
- analyse results
p<0.05
the probability that the results were due to chance is less than 5%
one tailed vs two tailed
one tailed = directional hypothesis as there is only one direction it can go in
two tailed = non-directional hypothesis as there is just a difference (doesn’t specify if it is a positive or negative difference)
sign test
- identify the three categories
- calculate the number of participants in each category
- assign the no difference category a 0 sign, and the other two a + and -
- eliminate the 0 category
- out of the two remaining categories, identify the category with the smaller number. this number is S
- S is your calculated value.
model conclusion
The calculated value of ______ is greater than/smaller than/equal to the critical value of _______ (p<________, _____ - tailed test, N =________). This means that the result is/is not significant. This means that we can accept/reject the null hypothesis that __________[null]______________________. [If your result is significant, you then add] This means that we can accept the alternative hypothesis that _________________[directional/non]________________________________________. However, because the significance level was ___[p<..]_______, there is still a ______[less than.. %]_________ probability that the results would have occurred even if _____[null]________________.
choosing stats tests
need to consider
1. level of measurement
2. is it a difference (experiment), correlation (relationships between ordinal or interval) or association (relationships between 2 nominal)
3. experimental design: related (matched pairs or repeated measures)(correlation), unrelated (independent groups)(association)
stats table
Can Surfers Catch More Waves Surfing Under Real Pressure
Chi-squared, Sign test, Chi-squared (association)
Mann-Whitney, Wilcoxon, Spearman’s rho (correlation)
Unrelated t-test, Related t-test, Pearson’s r (correlation)
Table reads:
level of measurement down the left side: nominal, ordinal, interval
across the top: test of difference (unrelated), test of difference (related) test of correlation or association (correlation - data is related, association - data is unrelated)
errors
type 1 error - null hypothesis is REJECTED and the alternative hypothesis is ACCEPTED when the null hypothesis is actually true. often happens when the significance level is larger than 0.05. (optimists)
type 2 error - null hypothesis is ACCEPTED but should have been REJECTED because the alternative hypothesis is actually true. happens when the sig level is smaller than 0.05. (pessimists)
errors model conclusion
- Currently, we are approximately ______% confident in our rejection of the null hypothesis because a ________ significance level has been used. This means that there is still a less than _____% probability of rejecting the null hypothesis when it is true and making a type 1 error. To check this, a more stringent significance level of ______ should be used which reduces the probability of a type 1 error having been made to less than ____%, making us more confident that a type 1 error hasn’t been made. When this significance level is used, the calculated value of ____ is greater than/less than/equal to the critical value of _____ (p<________, ____-tailed test, N/df = _____). This means that the result is still significant/is no longer significant. This suggests that a type 1 error has been made and so the null hypothesis should be accepted/this suggests that a type 1 error is unlikely to have been made as there is only a less than ___% probability of this and so we can be more confident in rejecting the null hypothesis.
degrees of freedom
FORMULAS ARE GIVEN BUT:
chi-squared = (number of rows -1) x (number of columns -1). this DOES NOT include the title rows or columns so don’t include them in the calculation
unrelated t-test = Na + Nb - 2
related t-test = N - 1
NOTE: in Wilcoxon if a matched pairs design has been used then N is the number of pairs not number of participants
evaluating questions
- is the question open or closed
- does the question use a fixed choice option, a Likert scale or a rating scale (if the question is closed)
- is the data quantitative (closed) or qualitative (open)
- why? (double negative, double barrelled, lack of clarity, technical jargon, emotive language, small range of options, relies on another question)
- reword
scientific cycle of enquiry
- theory construction
- hypothesis testing
- empirical method
- objectivity
- replicability
psychological report
abstract - summary of the study
introduction - review of relevant previous research
method
results
discussion - interpret results
references
appendices - materials and raw data
