Statistical techniques Flashcards
(22 cards)
What does a low standard deviation show
Low standard deviation shows greater reliability as points are closely grouped to the mean
what is standard deviation
a measure of the variation around the mean
What is a high standard deviation
data points has a larger range, lower reliability
what is this called
(standard deviation)
Confidence limits- determine the range around the mean
what is a null hypothesis
this is a statement of what we would expect if there is no significant difference. And if there was to be a difference it is due to chance not correlation
what does the x with the line above it stand for
Mean
what is a t-test
compare the means of two sets of data to determine whether they are significantly different or not.
what test needs to be carried out before a t-test
Standard deviation
when do we reject a null hypothesis
when there is a statistically significant difference between the two sets of data.
And when the
what is the difference between paired and unpaired
Paired- data between two groups which are the same
Unpaired- data between two different groups
when the t test value is higher than the critical value what hypothesis will be accepted.
accept H1 (alternative hypothesis).
what is a one tailed test
a test where you know which direction the difference is going in
what is a two tailed test
A test where you dont know which direction the difference is going
what does significant difference mean
It means there is a factor causing this difference not by chance
what does the x-x̄ mean?
X= 1 value of data
x̄=mean
what does the n stand for?
n= The total amount of values of data
E.G- In a graph, there is 15 data results, 15-1
When finding critical values, what is the probability we always use in Biology
0.05
When do we accept H0 and when do we reject H0.
T-test < critical value (Accept H0).
T-test> critical value (reject).
how do you work out a degree of freedom for a paired t test
n-1
how do you work out a degree of freedom for a unpaired t test
n1-n2-2
what is the reason we use the spearmans rank correlation coefficient
Looking if there is a association/ correlation between two sets of data
what is the purpose of statistical tests
determine if a relationship is due to chance or an outside factor effecting organisms- effecting the significance of the data
