Question

PLEASE help ! :)

How do I construct a 98% confidence interval with two independant simple samples with normally distributed populations with sigma1=sigma2 (o1=o2)??

How do I figure out the t score when it is 0.01 significance level and degrees of freedom=394??

Answer 1

I do not understand
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[FLIP TABLE RAGE!]

Answer 2

shh it's ok. no need to spam... @Dbzfan836

Answer 3

can't help though sorry. i don't know statistics...

Answer 4

oh, ok
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[put back the table]

Answer 5

wait, what!?!?
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[DOUBLE TABLE FLIP RAGE!]

Answer 6

you could get suspended for typing like that...

Answer 7

never mind...
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[put back the table]

Answer 8

sorry

Answer 9

Its pretty much the same as you would with just a single sample.

Answer 10

Do you own a graphing calculator?

Answer 11

no

Answer 12

Im really just having a hard time understanding what and where to find the t value to use in the formulas

Answer 13

I ask if you have a graphing calculator because, if it is a TI, then it could probably calculate it for you. Your sample size is much greater than 30, why not just use a z-interval?

Answer 14

Because i need t for the formula i am using

Answer 15

http://mips.stanford.edu/courses/stats_data_analsys/principles/t_table.html

http://allianthawk.org/victionary/showdef.php?word=217

Look at the critical values of the second page, and then look at the t scores corresponding to the popular significance levels. See how when df becomes close to 30, the t table values converge to the z table values? This is the Law of Large Numbers in play.

Answer 16

I dont use z scores

Answer 17

I need to use a t score for this formula

Answer 18

What is the formula? Is it (x1 − x2) ± t* × √(s1 ⁄ n1 + s2/ n2) ?

Answer 19

Basically, what I am saying, is that when df > 30, there is no significant difference between using t-scores and z-scores.

Answer 20

When you have a left tailed test, and find your t score, Do you change it to become negative?

Answer 21

Your t-score will be negative, since it is below the mean difference.

Answer 22

okay thanks!