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Given Information:
Population size = n = 300
standard deviation = σ = 15
confidence level = 99%
Required Information:
Margin of error = ?
Step-by-step explanation:
The margin of error is a measure of the effectiveness of your survey.
Margin of error = z*(σ/√n)
z-score corresponding to 99% confidence level = 2.58
Margin of error = ±2.58*(15/√300)
Margin of error = ±2.58*(0.866)
Margin of error = ±2.23
Hence the correct option is C ±2.23
Step-by-step explanation:
a+b+c=78
b=10+a
c=2b
then, we back the first
a+10+a+2b=78
2a+2b=78- 10
2a+2(10+a)=68
2a+2a=48
4a=48
a=12
b=22
c=44