Question

A newsgroup is interested in constructing a 90% confidence interval for the difference in the proportions of Texans and New Yorkers who favor a new Green initiative. Of the 605 randomly selected Texans surveyed, 396 were in favor of the initiative and of the 579 randomly selected New Yorkers surveyed, 457 were in favor of the initiative.

a. With 90% confidence the difference in the proportions of Texans and New Yorkers who favor a new Green initiative is between (round to 3 decimal places) and (round to 3 decimal places).

b. If many groups of 605 randomly selected Texans and 579 randomly selected New Yorkers were surveyed, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population proportion of the difference in the proportions of Texans and New Yorkers who favor a new Green initiative and about percent will not contain the true population difference in proportions.

Answer 1

The statistical software output for this problem is:

From above output:

a) 90% confidence interval:

(-0.177, -0.092)

b) First blank = 90

Second blank = 10