In: Math
According to a PARADE poll of 1200 Americans, 75% of the respondents claimed that they had changed their behavior I an attempt to lower their risks of heart disease. Assume that these 1200 people represent a random sample.
a.) find a 98% confidence interval for the percentage of all Americans who say that they have changed their behavior to lower their risks of heart disease.
We have given,
n=1200
Estimate for sample proportion= 0.75
Level of significance is =0.02
Z critical value(using Z table)=2.326
Confidence interval formula is
=(0.7209 , 0.7791)
Lower limit for confidence interval=0.7209
Upper limit for confidence interval=0.7791