The <em><u>correct answer</u></em> is:
c)75.4 to 94.6
Explanation:
The formula for a confidence interval is:
,
where μ is the mean, z is the z-score associated with the level of confidence we want, σ is the standard deviation, and n is the sample size.
Our mean is 85, our standard deviation is 12, our sample size is 6, and since we want 95% confidence, our z-score is 1.96:
First move the constant to the other side causing it to change sides
4x<-6-6
Then calculate the difference (-6-6)
4x<-12
Now divide both sides by 4
X<-3
Then you are left with your answer:
x<-3
Hope this helps! :3
IF you are solving for d:
isolate the D, do the opposite of PEMDAS.
-d/6 + 12 = -7
(subtract 12 from both sides)
-d/6 + 12 (-12) = -7 (-12)
-d/6 = -19
(multiply 6 to both sides)
-d/6(6) = -19(6)
-d = -19(6)
-d = -144
-d/-1 = -144/-1
d = 144
hope this helps
