What do I plug into a calculator to find the value of 831 after a 12% increase?
2 answers:
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Answer:
31.92%
Step-by-step explanation:
We are given;
Population mean; μ = $3.12
Sample mean; x¯ = $3.16
Sample size; n = 10
Standard deviation; σ = $0.27
Z-score formula is; z = (x¯ - μ)/(σ/√n)
z = (3.16 - 3.12)/(0.27/√10)
z = 0.04/(0.08538)
z ≈ 0.47
Now, the percent of other sample means, based on 10 gas stations, that would be greater than the one observed is;
P(x¯ > 3.12) = 1 - P(z < 0.47)
From z-table attached P(z < 0.47) = 0.68082
Thus;
P(z > 0.47) = 1 - 0.68082
P(z > 0.47) ≈ 0.3192
This expressed in percentage is 31.92%
