Question

This seems like to many cans to the company, so they test 100 and find that 62 have 12 oz or more. Construct a 90% confidence interval for the proportion of cans that have at least 12 oz of cola.

This interval still did not produce the desires margin of error of 3%. With this new estimate, how many cans (total) should they measure now to achieve a 90% confidence interval that is within 3% of the true proportion?

Answer 1

a).given data are:-

sample proportion () = 62/100 = 0.62

sample size (n) = 100

z critical value for 90% confidence level, both tailed test be:-

the 90% confidence interval for the proportion of cans that have at least 12 oz of cola be:-

b).given data are:-

= 0.62 , E = 3% = 0.03

the needed sample size be:-

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