Answer:
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 9 - 1 = 8
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 8 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 1.8595
The margin of error is:
M = T*s = 1.8595*2.7 = 5
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 25.3 - 5 = 20.3 milligrams
The upper end of the interval is the sample mean added to M. So it is 25.3 + 5 = 30.3 milligrams.
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.
Answer:
C
Step-by-step explanation:
y-3=5(x-2) (rearrange this to be in slope- intercept from) (add 3 to both sides)
y = 5(x-2) + 3 (distribute parentheses)
y = x(5) - 2(5) + 3
y = 5x -10 + 3
y = 5x - 7
recall that for a line with gradient m, the gradient of the perpendicular line will be - (1/m)
hence in our case, our gradient of the original line is 5, hence the gradient of the perpendicular line is -1/5
From the choices, the only one that is consistent with this is C
i.e choice C:
5y + x = 25
5y = -x + 25
y = -(1/5) x + 5 ===> gradient of -1/5
20: 30-4 x (2+5)=2
21. 17-(8-5)= 14
22. You put (10/2)-3+1, but it isn't necessary
Explanation: to solve these equations, use PEMDAS (parentheses, exponents, multiplication, division.) these equations don't involve exponents, though, so ignore that part. If 30 is left alone, you would multiply 4x2 before doing anything else. This would mean you would have 30-8+5' which gets you to 27, an incorrect answer. However, if you put parentheses around (2+5), you add those first, meaning you would then have 30-4(2+5) = 30-4(7) = 30-28= 2.
Try to do the rest; if you're still having trouble add a comment
Answer:
see above there is the answer sorry for rough
