How do you find the Lower bound and the Upper bound of a confidence interval?
n=1000 x=0.16 s= 0.07

Question

How do you find the Lower bound and the Upper bound of a confidence interval?
n=1000 x=0.16 s= 0.07

amistre64 · Answer

a confidence interval requires a level of significance

amistre64 · Answer

that looks to be a mean, and a standard deviation of the sample?

amistre64 · Answer

$$CI=\bar x\pm E$$
$$CI=\large \bar x\pm t~\sqrt{\frac{s^2}{n}}$$

amistre64 · Answer

used to be able to get away with a z value instead of a t value for n>30,  but there is some grief about doing that these days

anonymous · Answer

i forgot to  put that it said to" determine and interpret a 90% confidence interval" can I use the same formula for that ?

amistre64 · Answer

yes, the z or t value is determined from the 90% information

is that s, or $\sigma$ ?

if its an s, we should use a t distribution value, if its a sigma we can use the z distributions

anonymous · Answer

its an s

amistre64 · Answer

unless youve got some tech at your disposal, the t value can be tabled

amistre64 · Answer

got a ti83?

anonymous · Answer

yep do i use the 2nd vars button on my calculator

amistre64 · Answer

stats, tests, t interval

amistre64 · Answer

t interval is 8 on mine ... not 2 :)

anonymous · Answer

do I use ( tpdf )

amistre64 · Answer

no, 2nd vars gets you to the distribution menus ... you dont need those

you want to perform stat tests

anonymous · Answer

is that under  L1 ?

amistre64 · Answer

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