Answer:
138
Step-by-step explanation:
Population standard deviation = 
.95 probability of estimating the population mean monthly income within a margin of $20
So, Significance level = 1-0.95 = 0.05
α =0.05
Margin error = 20

Z at 0.05 = 1.96




So, n = 138
Hence sample size should be 138 selected to obtain a .95 probability of estimating the population mean monthly income within a margin of $20
Answer:
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Answer:
y = − 8
Step-by-step explanation: