Sub: Statistics Topic: Testing
Test the proportion of customers favoring underground installation is more
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A telephone company is trying to decide whether some new lines in a large community
should be installed underground. Because a small surcharge will be added to the phone bills
to pay for the extra installation costs the company has decided to survey customers and
proceed only if the survey strongly indicates that more than 60% of all customers favor
underground installation. In a random sample of 160 customers, 115 favor underground
installation in spite of the surcharge.
-Construct a 99% confidence interval for the proportion of customers favoring underground
Given that, x : number of customers favoring underground installation = 115
And n : sample size = 160.
So, p 0.71875.