Let X be the length of needle produced by machine. X follows Normal distribution with standard deviation σ=0.01
The margin of error ME = 0.005 and confidence interval is 95%
We have to find here sample size n from given information
The formula to find sample size when population standard deviation is known is
n =![[\frac{z_{\alpha/2} standard deviation}{ME}] ^{2}](https://tex.z-dn.net/?f=%20%5B%5Cfrac%7Bz_%7B%5Calpha%2F2%7D%20standard%20deviation%7D%7BME%7D%5D%20%5E%7B2%7D%20%20%20%20)
where 
is critical z value for 95% confidence interval
We have confidence level, c=0.95
α = 1- c = 1-0.95 = 0.05
α/2 = 0.05 /2 = 0.025
z (0.025) is z score value for which probability below -z is 0.025 and above z is 0.025
Using z score table to get z critical value
z = -1.96
For confidence interval calculation we use positive z score value 1.96
The sample size will be then
n = ![[\frac{1.96 * 0.01}{0.005}]^{2}](https://tex.z-dn.net/?f=%20%5B%5Cfrac%7B1.96%20%2A%200.01%7D%7B0.005%7D%5D%5E%7B2%7D%20%20)
n = 15.3664
Rounding sample size to nearest integer n=15
a sample is needed to determine with a precision of ±0.005 inches the mean length of the produced needles to 95% confidence is 15
The sum its +2
2+2=4
4+2=6
6+2=8
8+2=10
And so on the numbers just keep sum for 2
I believe this is the question: "Quadrilateral ABCD in the figure below represents a scaled-down model of a walkway around a historic site. Quadrilateral EFGH represents the actual walkway. ABCD is similar to EFGH. Two irregular similar quadrilaterals ABCD and EFGH are drawn. AB measures 5 inches, BC measures 4 inches, CD measures 4 inches and AD measures 3 inches. EF measures 45 feet. What is the total length, in feet, of the actual walkway?"
We should determine the ratio(proportionality) of the two similar quadrilaterals. Since AB corresponds to EF, AB=5, EF=45, we know that the side lengths of EFGH is 45/5=9 times those of ABCD. The perimeter of ABCD=5+4+4+3=16 feet, so the perimeter of EFGH, the actual pathway, is 16*9=144 feet.
9514 1404 393
Answer:
(a) 3/2
Step-by-step explanation:
The scale factor is the ratio of corresponding side lengths.
sf = 63/42 = (21×3)/(21×2) = 3/2
The answer is most likely c
