The Labor federal government introduced a scheme that put a price on carbon emissions (a "carbon tax") that came into effect on 1 July 2012. This scheme was subsequently dismantled by the Coalition government that won power in September 2013. Prior to the passing of the legislation that put in place the carbon pricing scheme and its dismantling, professional polling organisations such as Newspoll would regularly ask Australian voters whether or not they supported the introduction of a carbon pricing scheme. The results of the poll taken between 12 and 14 July 2013 are below:

Survey Date	In Favour	Against	Undecided	Sample Size
29 Apr - 1 May 2011	362	651	193	1206
8 Jul - 10 Jul 2011	367	612	245	1224
22 Jul - 24 Jul 2011	450	688	112	1250
21 Oct - 23 Oct 2011	390	720	111	1221
12 Jul - 14 Jul 2013	408	636	156	1200

Construct 95% confidence interval estimates of the total percentage of Australian voters against a carbon price (TOTAL AGAINST) for the time periods 21-23 October 2011 and 12-14 July 2013. Provide evidence to support any assumptions that you make when constructing your intervals. Interpret your estimates in words and discuss briefly what your estimates might imply for whether opposition to a price on carbon changed between the two periods.