confidence level 80% 90% 95%% 99% 99.9% area to left .90 .95 975 .995 9995 area to right .10 05 .025 005 0005 critical value z" 1.282 1.645 1.960 2.576 3.291 In a survey of 500 American households, 68.5% of the households claimed to have made a financial contribution to charity Describe the parameter value of interest in this situation. Show Your Work In a survey of 500 American households, 68.5%% of the households claimed to have made a financial contribution to charity. If the survey had involved 500 households, what would a 99% confidence interval of this parameter be? Show Your Work