analysing data : graphs, sign test Flashcards
What is a bar chart and when is it used ?
Used when data is divided into categories(discrete data )
a title is needed for a bar chart
the bars aren’t touching
What are scattergraphs and when are they used?
Show association between co variables
shows relationship between variables
What a skewed distribution curve ?
A spread of frequency data that is not symmetrical
it’s where data clusters to one end
What is a negative skew distribution curve ?
Long tail is on the left side and most of the distribution is on the right
the mean is lower than the median and mode
what is a positive skewed disribution curve?
the long tail is on the right side
the mean is higher than the median and mode
What is the symbol that shows equality
=
Which symbol shows much greater than
> >
Which symbol shows much less than
«
Which symbol means proportionate to ?
∝
Which symbol means a a weak approximation ?
approximately equal
≈
What is the level of significance in psychology ?
0.05 / 5%
What are the 5 steps of the sign test ?
1.Work out the sign. Have the values gone up (+) down (-) or stayed the same (=)
2.calculate the “ s” score. This is the lowest score excluding any nil scores
3.calculate the value on N the total number of values the (+) add the (-) excluding any with no difference
4.find the critical s value using the table
5.determine whether results are significant : The value of s must be equal too or Lower than the critical s value
What is the strength of a median ?
Not affected by extreme scores so the average is more realistic of the data set
When should the mode be used ?
Nominal data - data is in categories
What are the 2 measures of dispersion ?
Range
standard deviation
What is a normal distribution curve ?
A symmetrical spread of frequency data that forms a bell shaped pattern.
The mean median mode are located at the highest peak.
what is the symbol for probability?
P
What are the limitations of correlations?
Third variable problem : another unknown variable that is causing the correlation between the other 2 variables “ intervening variable “
doesn’t show cause and effect it only shows the relationship
What is the limitation of a meta analysis ?
Publication bias
where the researcher may not choose to review all information but may leave out thise thaf don’t have significant results
What is the strength of using a mean ?
The most sensitive of all the measures of central tendency as it includes all the scores therefore is is the most representative of a whole data set
What is the limitation of using the mean ?
Easily distorted by extreme values this isn’t good as it stops the mean from being representative of the whole data
What is a strength of using the range ?
Easy to calculate
What is a histogram and when Is it used ?
Used for frequency
The bars touch eachother which shows the data is continuous and not discrete
y axis represents frequency
x Asis is equal sized intervals of a single category
What is a line graph ?
Represents continuous data
uses points and connects it by a line
Shows how something changesin value
iv on x axis
dv on y axis
What is a zero correlation ?
The variables have no relationship with eachother
What are the strengths of correlations ?
Good way of showing relationships so we can investigate further e.g in an experiment
Quick And economical there is no need for an experiment as it is mostly looking at secondary data
What are the 3 measures of central tendency ?
Mode
median
mean
Which symbol means greater than?
>
Which symbol means less than?
<
What is a weakness of standard deviation ?
Can be swayed by extreme results
What is the scale for correlation co efficient ?
strong negative -0.1
-0.8 is great
-0.5 negative correlation
0.0 zero
0.5 positive correlation
0.8 is great
1.0 positive correlation
What is considered a great correlation co efficient ?
0.8 and -0.8
What is a weakness of using a median ?
Less sensetive than the mean as not all scores are included In the final calculation
