Question

Paul wants to compare whether the prices of tangerines in two supermarkets differ significantly. He has been noting down the daily prices for the last few days and has found the difference in the sample means to be 20 cents. If the standard deviation of the distribution of the difference between sample means is 28 cents and we are testing the null hypothesis at the 95% confidence level, which statement is true?

Answer 1

A.The difference between the two means is significant at the 95% confidence level, so the null hypothesis must be rejected.
B.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be rejected.
C.The difference between the two means is not significant at the 95% confidence level, so the null hypothesis must be rejected.
D.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be accepted.
E.The difference between the two means is significant at the 95% confidence level, so the alternative hypothesis must be rejected

Answer 2

@amistre64

Answer 3

this one

Answer 4

yea

Answer 5

do you recall what i have been saying about the empirical rule?

68-95-99 and their respective standard deviations?

Answer 6

whats the empirical rule...

Answer 7

its the rule that i have been stating time and time again .... its a rule that tells us an approximation of the probability that the amount of data is between 1,2, or 3 standard deviations from the mean

Answer 8

like the formula that is ?/sqrt(n)

Answer 9

that formula

Answer 10

no, just the simple rule:

68% of the data falls within 1 sd of the mean
95% of the data falls within 2 sd of the mean
99% of the data falls within 3 sd of the mean

an sd is like a ruler, a measuring stick, a way to measure how far away something is from the mean

Answer 11

where does 1 sd and 2 sd, etc fall into place

Answer 12

a 95% confidence interval is approximately equal to: 2 sds from the mean.



|-----95% C-level-------|
-2sd 2sd
<------- mean-------->


they tell us that 1 sd is equal to 28, and that the mean is equal to 20; so lets fill this in



-2sd 2sd
<------- mean-------->
-2(28) 20 2(28)

Answer 13

i have a little error in my pictorial view

Answer 14

so how does that show if it rejected or accepted

Answer 15

the mean is zero; if the difference between the means is within 2(28), we fail to reject the null

Answer 16

so if you fail to reject the null does that mean its accepted

Answer 17

correct enough yes; if we fall within the boundaries we accept the null, if we go out side of the bounds, we reject the null

Answer 18

20/28 is obvious less then 2 so we fall within the 95% boundary condition and "accept" the null

Answer 19

that make sense since only one of the answer choices is accept

Answer 20

either accept the null, or reject the alternative

B.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be rejected.

C.The difference between the two means is not significant at the 95% confidence level, so the null hypothesis must be rejected.

D.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be accepted.

E.The difference between the two means is significant at the 95% confidence level, so the alternative hypothesis must be rejected

Answer 21

wait what?

Answer 22

E is out as well, and please quit harassing the chat box

Answer 23

there annoying me lol but alright

Answer 24

the difference is not significant; so we are left with these 3

B.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be rejected.

C.The difference between the two means is not significant at the 95% confidence level, so the null hypothesis must be rejected.

D.The difference between the two means is not significant at the 95% confidence level, so the alternative hypothesis must be accepted.
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either the null is accepted; OR the alternative is rejected

B. the alternative hypothesis must be rejected.; yes

C. the null hypothesis must be rejected.; no

D. the alternative hypothesis must be accepted. ; no

Answer 25

so every problem like ths is null accepted or rejecteD?

Answer 26

i just dont bother going in and playing in the chatbox to begin with ... everytime i open it i can feel my iq drop

Answer 27

well, the wording might have to be interpreted; but yes

Answer 28

lol idk me and ponder were just messin with them lol