Answer:
The confidence interval for the population variance of the thicknesses of all aluminum sheets in this factory is Lower limit = 2.30, Upper limit = 4.83.
Step-by-step explanation:
The confidence interval for population variance is given as below:
![[(n - 1)\times S^{2} / X^{2} \alpha/2, n-1 ] < \alpha < [(n- 1)\times S^{2} / X^{2} 1- \alpha/2, n- 1 ]](https://tex.z-dn.net/?f=%5B%28n%20-%201%29%5Ctimes%20S%5E%7B2%7D%20%20%2F%20%20X%5E%7B2%7D%20%20%5Calpha%2F2%2C%20n-1%20%5D%20%3C%20%5Calpha%20%3C%20%5B%28n-%201%29%5Ctimes%20S%5E%7B2%7D%20%20%2F%20X%5E%7B2%7D%201-%20%5Calpha%2F2%2C%20n-%201%20%5D)
We are given
Confidence level = 98%
Sample size = n = 81
Degrees of freedom = n – 1 = 80
Sample Variance = S^2 = 3.23
![X^{2}_{[\alpha/2, n - 1]} = 112.3288\\\X^{2} _{1 -\alpha/2,n- 1} = 53.5401](https://tex.z-dn.net/?f=X%5E%7B2%7D_%7B%5B%5Calpha%2F2%2C%20n%20-%201%5D%7D%20%20%20%3D%20112.3288%5C%5C%5CX%5E%7B2%7D%20_%7B1%20-%5Calpha%2F2%2Cn-%201%7D%20%3D%2053.5401)
(By using chi-square table)
[(n – 1)*S^2 / X^2 α/2, n– 1 ] < σ^2 < [(n – 1)*S^2 / X^2 1 -α/2, n– 1 ]
[(81 – 1)* 3.23 / 112.3288] < σ^2 < [(81 – 1)* 3.23/ 53.5401]
2.3004 < σ^2 < 4.8263
Lower limit = 2.30
Upper limit = 4.83.
X + y = 1
x + 3y = 9
Subtract the second equation from the first.
-2y = -8
divide both sides by -2
y = 4
Plug 4 back into either equation and solve for x.
x + y = 1
x + 4 = 1
subtract 4 from each side
x = -3
(-3, 4)
Answer: A)
The first one because the x don’t repeat
Answer:
The goal in solving an equation is to get the variable by itself on one side of the equation and a number on the other side of the equation. To isolate the variable, we must reverse the operations acting on the variable. We do this by performing the inverse of each operation on both sides of the equation.
Reverse addition and subtraction (by subtracting and adding) outside parentheses. Reverse multiplication and division (by dividing and multiplying) outside parentheses. When multiplying or dividing by a negative number, flip the inequality sign. It does not matter if the number being divided is positive or negative
It's necessary to apply inverse operations on both sides of the equals signs so that you can solve for the variable and balance the equation.
Multi-step inequalities are solved using the same processes that work for solving equations with one exception. When you multiply or divide both sides of an inequality by a negative number, you must reverse the inequality symbol. (Much like when you divide by a negative number, the sign of the inequality must flip! Here's why: When you multiply both sides by a negative value you make the side that is greater have a "bigger" negative number, which actually means it is now less than the other side!)
Answer: 1639.08
Step-by-step explanation: To find the surface area of a cylinder, multiply 2(3.14)times the radius squared. Your answer is 508.68. Then multiply 2(3.14)times the radius and the height. You'll get 1130.08. add the answers you got from both equations together. That's the surface area of your cylinder. If you have any more questions, please let me know.
