Question

1. Of the 400 customers who were randomly surveyed, 110 believed that air polution was not a problem.

i. Calculate a 99% confidence interval for the true proportion of all American that believe that air polution is not a problem. Show workings pls

ii. Provide a plain language interpretation of the interval you constructed in part i.

iii. In part i, we have used a confidence level of 99%. What does the confidence level mean? Do we always use 99%? Explain.

Answer 1

i)

ii) true population proportion lies between 21.7 % and 33.3%.

iii)we are 99% confident that true population proportion lies between given confidence interval bounds. it means that out of 100, 99 observations proportion lies between confidence interval.

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