Answer:
2401
Step-by-step explanation:
Given that we want to estimate average income in a population.
The standard deviation of income in the population is $1,000
We want confidence interval around our estimate to be +/- $40
i.e Margin of error = 40
We know that margin of error = Std error * Z critical for 95%
i.e. 
Std error = 
Together we get
Answer:
1.2 lbs
Step-by-step explanation:
This problem is set up so that the total price is proportional to the price per pound, so to find the proportion you would divide the total cost by the cost per pound. 3.42/2.85 = 1.2, so the answer is 1.2 pounds.
the example on your picture uses A(n) and n = years, but is pretty much the same, in this case is t = years.
The paraboloid meets the x-y plane when x²+y²=9. A circle of radius 3, centre origin.
<span>Use cylindrical coordinates (r,θ,z) so paraboloid becomes z = 9−r² and f = 5r²z. </span>
<span>If F is the mean of f over the region R then F ∫ (R)dV = ∫ (R)fdV </span>
<span>∫ (R)dV = ∫∫∫ [θ=0,2π, r=0,3, z=0,9−r²] rdrdθdz </span>
<span>= ∫∫ [θ=0,2π, r=0,3] r(9−r²)drdθ = ∫ [θ=0,2π] { (9/2)3² − (1/4)3⁴} dθ = 81π/2 </span>
<span>∫ (R)fdV = ∫∫∫ [θ=0,2π, r=0,3, z=0,9−r²] 5r²z.rdrdθdz </span>
<span>= 5∫∫ [θ=0,2π, r=0,3] ½r³{ (9−r²)² − 0 } drdθ </span>
<span>= (5/2)∫∫ [θ=0,2π, r=0,3] { 81r³ − 18r⁵ + r⁷} drdθ </span>
<span>= (5/2)∫ [θ=0,2π] { (81/4)3⁴− (3)3⁶+ (1/8)3⁸} dθ = 10935π/8 </span>
<span>∴ F = 10935π/8 ÷ 81π/2 = 135/4</span>
