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.
Answer:
1) 102.7 meters
2) 11
Step-by-step explanation:
1) -4.9x² + 75x = -4.9x² + 50x + 38
25x = 38
x = 1.52 s
Height = -4.9(1.52)² + 75(1.52) = 102.67904 m = 102.7 m
2) f(x) = x² + 3x - 2
f(2) = 2² + 3(2) - 2 = 8
f(6) = 6² + 3(6) - 2 = 52
Average rate of change:
(52-8)/(6-2) = 11
Answer:
cost = 8p + 5
Step-by-step explanation:
$8*[number of pizzas] + $5 delivery fee
$8p + $5
8p + 5
cost = 8p + 5
Answer:
D
Step-by-step explanation:
since it's a multiplication consider the two factors one by one
cubic root of y^6 = y^(6/3) = y^2
cubic root of 8x^3= 2x^(3/3)= 2x
so 2xy^2
Answer:9400 backpacks
Step-by-step explanation
since the number of packs to be sold in a is represented by x,
selling price for 1 week = 35x
cost price for 1 week = 15x
profit = 35x-15x = 20x
additional cost of production = 11,000
this implies that 20x - 11,000 7800
20x - 11,000 7,800
20x 7800+ 11000
20x 18,800
x 18800/2
x 9,400
at least 9,400 packs have to be sold each week to make a profit of $7800
