U2T8 - Statistics

Question 1

Why must experimental results be analysed?

Answer 1

Ensures results can be treated objectively + avoids bias when drawing conclusions.

Question 2

What is the equation for standard error?

Answer 2

Standard Error = the square root of (population variance divided by the number of samples)

Question 3

What is the equation for the estimation of population variance?

Answer 3

Population Variance = (the sum of sample value - sample mean) divided by (num of sample - 1)

Question 4

What is the equation for 95% confidence limits?

Answer 4

95% Confidence Limits = sample mean plus or minus t times the standard error.

Question 5

What is the equation for the student’s t test?

Answer 5

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)

Question 6

How do you work out the degrees of freedom for the t test?

Answer 6

((n1+n2)-2)