Statistics Flashcards
(29 cards)
Mean
Add all values together and divide by how many there are
Median
the middle value (average middle 2 if odd number of values
Mode
the most frequently observed value
Range
the range in values (maximum and minimum)
Standard deviation
estimate of the average variability (spread) of the data
95% confidence interval
the range of values around that statistics (so 95% of values will fit into between the range of values)
Standard error
Standarderrorthestandarddeviationofthesamplingdistributionofagiven statistics
P value
-the probability of falsely rejecting the null hypothesis
-The null hypothesis is that there is no difference
- P < 0.05 is described as significant.
- P < 0.05: Essentially if its less than 0.05%. Therefore, you are 99.95% sure there is a significant difference!
Normal distribution
• Important for quantitative data
• Ensures that data is representative of a “normal” population
• Helps determine how we present data
• Helps determine what statistical test we would use to analyse data
Tests for normal distribution
-Kolmogorov-Smirnov test Or Shapiro-Wilk test
What does it mean if they value is significant
it indicates the sample is NOT normally distributed
Normal distribution on SPSS
-copy data into SPSS
-click analyse
-descriptive statistics then explore
-add variables into the dependent list
-click on plots with tests,histogram an then continue
Parametric
• If our data is normally distributed we choose “PARAMETRIC” tests
Non parametric
If our data is not-normally distributed we choose “NON-PARAMETRIC” tests
Type 1 error
Occurs when we believe that there is a genuine effect in our population, when in fact there isn’t
Type 2 error
Occurs when we believe there is no effect in the population, when there is
Two tailed
= A test of a non-directional hypothesis, i.e. x may or may not predict y or x is maybe different from y
One tailed
= A test of a directional hypothesis, i.e. x will predict y or x is different from y
What is statistics
Collection,organisation,analysis,interpretation and presentation of data
How to calcite mean.mode range on SPSS
-copy data into SPSS
-analyse, descriptive statistics ,explore
-click the arrow to add variables into the dependent list
-click statistics and press ok
How to determine if ur data is paired(dependent) or unpaired(independent)
Compare participants in different group
>they are independent from each other,different people in each groups receiving different types of treatment
Compare participants in the same group
>they are dependent same people tested twice receiving the same treatment
Tip:if it has a control group it is independent
T test(2 types depending on whether your data is independent or dependant)
-independent t-test= as your data is independent from each other eg different groups
-dependent t test=as your data is dependent on each other
what type of data is t Test used for
Parametric
How do u determine if the data is parametric
Complete a Kolmogorov-Smirnov or Shapiro-wilk test to see if the p value is significant,if its not it means its normally distributed so its parametric
