a)
sample success x = | 123 | ||
sample size n= | 1130.0 | ||
pt estiamte p̂ =x/n= | 0.10885 | ||
se= √(p*(1-p)/n) = | 0.0093 | ||
for 95 % CI value of z= | 1.960 | from excel:normsinv((1+0.95)/2) |
margin of error E=z*std error = | 0.018 | |
lower bound=p̂ -E = | 0.091 | |
Upper bound=p̂ +E = | 0.127 | |
from above 95% confidence interval for population proportion =(9.1 % ,12.7 %) |
b)
c)
d)
Do the mass mailing (since interval values are above 5%)
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