9 - further hyp tests + confidence intervals

Question 1

hyp test for mean of a large sample

Answer 1

H0 μ =
H1 μ !=/</>
sample mean ~N(μ, σ²)
find p
if p<sig level reject H0

Question 2

hype test for mean of a large sample assumptions

Answer 2

• data is draw from normal
• population variance is known
  (if n>25 you can use CLT or if you find the unbiased variance you can use that to bypass these assumptions)

Question 3

confidence interval

Answer 3

an interval that has a specified prop (eg 90%) of including the true pop value in it

Question 4

confidence interval method

Answer 4

(SM - Zσ/√n, SM + zσ/√n)
where SM = sample mean
find the Z value that gives 90% then do the conversion from Z world to normal

Question 5

width of confidence interval

Answer 5

2zσ/√n
midpoint is always the mean