U2T8 - Statistics Flashcards
Statistics
Why must experimental results be analysed?
Ensures results can be treated objectively + avoids bias when drawing conclusions.
What is the equation for standard error?
Standard Error = the square root of (population variance divided by the number of samples)
What is the equation for the estimation of population variance?
Population Variance = (the sum of sample value - sample mean) divided by (num of sample - 1)
What is the equation for 95% confidence limits?
95% Confidence Limits = sample mean plus or minus t times the standard error.
What is the equation for the student’s t test?
t = (sample mean 1 - sample mean 2) divided by the square root of (standard error of sample 1 squared + standard error of sample 2 squared)
How do you work out the degrees of freedom for the t test?
((n1+n2)-2)