Given:
Sample size, n = 40
Sample mean, xb = $6.88
Population std. deviation, σ = $1.92 (known)
Confidence interval = 90%
Assume normal distribution for the population.
The confidence interval is
(xb + 1.645*(σ/√n), xb - 1.645*(σ/√n)
= (6.88 + (1.645*1.92)/√40, 6.88 - (1.645*1.92)/√40)
= (7.38, 6.38)
Answer: The 90% confidence interval is (7.38, 6.38)
Answer:
10
Step-by-step explanation:
ab = a * b
if a is 2 and b is 5 then 2 * 5 = 10
C(x) = 4x³+7x²-14x-6
Step-by-step explanation:
Given that the amount of water used in normal days is given by the equation;
W(x) = 5x³ +9x²-14x +9 -----(i)
The amount of decrease in water used is modeled by the equation;
D(x)= x³+2x² +15--------(ii)
To get the function C(x) that models the water used by the car wash on shorter day you subtract equation (ii) from equation(i)
5x³ +9x²-14x +9
- x³+2x² +15
-------------------------
4x³+7x²-14x-6
Learn More
Subtraction in polynomials : brainly.com/question/2273346
Keywords : equation, modeled,
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