week 6 Flashcards
What does a small standard deviation
the mean is a good representation of the data
What is does a large standard deviation
a poor representation of the data
What two types statistics is there
Descriptive
Inferential
What is descriptive statistics
simply describe data
What is inferential statistics
make inferences on data
What are models
Model 1: two separate means best account for the data (there is an effect)
Model 2: one mean best accounts for all the data
what is systematic variation
the variation that can be explained by the model
What is unsystematic variation
the variation that cannot be explained by the model
What is the equation for test satistic
Test statistic= variance explained by the model/ variance not explained by the model
What do we do after it is a good model
We now calculate the probability of getting this statistic if the null hypothesis is true
How do we calculate probability
probability= frequency of the event occurring/ total number of event
What is the alpha
the alpha is the probability convention in psychology this is p<0.05
the alpha value is the probability of obtaining a sample statistic than observed, if the null hypothesis was true
What does it mean if the probability is less than the alpha level
it is statistically significant
What does it mean if the alpha level is less than the probability
it is not statistically significant
What is Beta and what is it
Beta=0.2
Beta= is the probability of making a type II error
means for p>0.05
we state we have no significant effect
We fail to reject the null-hypothesis
Means for P<0.05
We state we have a statistically significant effect
we reject the null-hypothesis
Our model is a possible explanation
What is a type 1 error
incorrect reason to reject the null hypothesis
what is type 2 error
incorrect reason to fail to reject the null hypothesis
What is effect sizes
quantitative measure of the magnitude of the experimental effect
What is Pearson’s r correlation coefficient
high r value means strong relationship between 2 variables
Low r value means weak relationship
What is Cohen’s d
size of the difference between two means relative to the variability
unlike p-value, not directly affected by sample size
allows comparison of size of effect across studies
recommend to report with t-test and ANOVA
