Lecture 6 Flashcards
Confidence Interval Estimates
What is estimation?
population parameter is UNKNOWN, sample stats is used to generate estimates of the unknown parameter
What is hypothesis testing?
explicit statement made about the POP parameter, sample stats are analyzed to decide whether to accept or reject the hypothesis about the parameter
What are the 4 components to estimations?
- point estimate
- confidence interval (CI%)
-level of confidence - margin of error
What is the general calculation for estimation (CI) ranges?
point estiamte +/- z or t * margin of error
What is the margin of error equation for a single sample z-distribution?
s (sd of sample) / root n (sample size)
How do you calculate t?
x-bar - mew / SE (standard error = s/root n)
What is the point estimate of two independent samples?
x-bar 1 - x-bar 2
What is the Sp equation for two independent samples?
root [(n1-1) s1^2 + (n2-1)s2^2] / n1+n2 -2
What is the margin of error for two independent samples?
Sp*(root (1/n1 + 1/n2)
What must be true of the variance with two independent samples?
variance check = s1^2 / s2^2 must be between 0.5 and 2
What is the df for two independent samples?
df = n1 + n2 - 2
What is the point estimate of matched samples?
X-bar d = sum of differencence (di) / n
What is the sd of matched samples?
root (sum of (di - xbar d)^2 / n-1)
What is the margin of error for matched samples?
z/t * sd / root n
What is the df of matched samples?
df = n -1
