Final Flashcards
(21 cards)
What is usually taken as the best estimate of population mean?
The mean of a single sample
What is the formula for standard error of mean (SEM)?
Stdev of pop (sigma thingy)/ Square root of size of sample (n)
What is usually taken as the best estimate of a population standard deviation?
Sample standard deviation
What is the central limit theorem for a normally distributed population?
If original pop. is distributed normally, sampling distribution of means will also be normal
What is the central limit theorem for a not normally distributed population?
If the original pop. is not distributed normally, the sampling distribution of means will increasingly approximate a normal distribution as sample size increases
How do you get a confidence interval?
Take your percentage and find that amount on a z distribution, multiply that by standard deviation
How do you find the standard deviation of your sample when using p and q?
p+q=1
Find q
Sp= SQRT ((p*q)/n)
How do you find t?
t= (mu (Pop. mean) - xbar (Sample mean))/ Standard deviation of xbar
How do you find standard deviation of xbar?
Standard deviation/ SQRT n (number of participants)
When is the null rejected in favor of the alternate hypothesis?
When t of n-1 is greater than the calculated t
When is the alternate hypothesis rejected in favor of the null hypothesis?
When t of n-1 is less than the calculated t
What is the formula for a t test with two n’s, means, and standard deviations?
t= (xbar 1 - xbar 2)
s xbar1-xbar2
What is the formula for the s xbar1-xbar2
SQRT (S1^2/n1 + S2^2/n2)
What formula for t do you use in a one sample t-test?
t= mu-xbar/ s xbar
What formula for t do you use in a t test of correlated samples?
t = Dbar (difference between correlated numbers)/Sdbar
What formula for s do you use in a t test of correlated samples?
Sdbar= Sd/ SQRT n
How many degrees of freedom do you have in a one sample t-test?
df=n-1
How many degrees of freedom do you have in a t test of independent samples?
df= n1 + n2 - 2
How many degrees of freedom do you have in a t test of correlated samples?
df=n(pairs) -1
What is the formula for testing the hypothesis that a correlation coefficient is statistically significant?
t = r/ (SQRT( 1-r^2/n-2))
What is the formula for the fisher ratio?
F= (Between mean square (or variance))/ (Within mean square (or variance))
