Question

in march 2003, the pew research group surveyed adult americans and asked, \do you believe the united states made the right or wrong decision to use military force in iraq?\ in a 1,282 adult portion of americans from the survey, 919 stated the united states made the right decision. the pew research group then asked the same question to a group of adult americans in august 2010. in a 1,282 adult portion of that survey, 535 believed the united states made the right decision. complete parts (a) and (b).
click here to view the standard normal distribution table (page 1)
click here to view the standard normal distribution table (page 2)
interpret the 90% confidence interval for the difference between the two population proportions, ( p_{2003}-p_{2010} )
choose the correct answer.
a. there is 10% confidence that the difference in the proportion of adult americans from 2003 to 2010 who believe the united states made the right decision to use military force in the country is between the lower and upper bounds of the interval
b. there is 90% confidence that the difference in the proportion of adult americans from 2003 to 2010 who believe the united states made the right decision to use military force in the country is between the lower and upper bounds of the interval
c. there is 90% confidence that the difference in the proportion of adult americans from 2003 to 2010 who believe the united states made the right decision to use military force in the country is greater than the lower bound
d. there is 10% confidence that the difference in the proportion of adult americans from 2003 to 2010 who believe the united states made the right decision to use military force in the country is greater than the lower bound

Explanation:

A confidence interval gives a range of values within which the true population parameter is likely to lie. A 90% confidence interval means that if we were to take many samples and construct confidence intervals in the same way, about 90% of those intervals would contain the true difference in population proportions.

Answer:

B. There is 90% confidence that the difference in the proportion of adult Americans from 2003 to 2010 who believe the United States made the right decision to use military force in the country is between the lower and upper bounds of the interval.