Answer:
he added the dimensions of the rectangle. He used the wrong formula. the formula he used was length + breadth. He should have multiplied by 2
6x + 8y +8
Step-by-step explanation:
Perimeter of a rectangle = 2 x (L + B)
L = length
b = breadth
2 (3x + 4y + 4. ) = 6x + 8y +8
2.5 * 3.5 = 8.75 or 8 3/4 inches long
Step-by-step explanation:
area of square = l^2
so 10^2
100cm^2
It’s 9.9 because 3 times 3.3 is 9.9
<span>n = 5
The formula for the confidence interval (CI) is
CI = m ± z*d/sqrt(n)
where
CI = confidence interval
m = mean
z = z value in standard normal table for desired confidence
n = number of samples
Since we want a 95% confidence interval, we need to divide that in half to get
95/2 = 47.5
Looking up 0.475 in a standard normal table gives us a z value of 1.96
Since we want the margin of error to be ± 0.0001, we want the expression ± z*d/sqrt(n) to also be ± 0.0001. And to simplify things, we can omit the ± and use the formula
0.0001 = z*d/sqrt(n)
Substitute the value z that we looked up, and get
0.0001 = 1.96*d/sqrt(n)
Substitute the standard deviation that we were given and
0.0001 = 1.96*0.001/sqrt(n)
0.0001 = 0.00196/sqrt(n)
Solve for n
0.0001*sqrt(n) = 0.00196
sqrt(n) = 19.6
n = 4.427188724
Since you can't have a fractional value for n, then n should be at least 5 for a 95% confidence interval that the measured mean is within 0.0001 grams of the correct mass.</span>
