Cocaine users commonly snort the powder up the nose through a rolled-up paper cu
ID: 3152152 • Letter: C
Question
Cocaine users commonly snort the powder up the nose through a rolled-up paper currency bill. Spain has a high rate of cocaine use, so it’s not surprising that euro paper currency in Spain often contains traces of cocaine. Researchers collected euro bills in each of several Spanish cities. In Madrid, 17 out of 20 bills contained traces of cocaine. The researchers note that we can’t tell whether the bills had been used to snort cocaine or had been contaminated in currency-sorting machines. Take p to be the proportion of all Spanish euro bills that contain cocaine traces.
Why can we not use the large-sample formula for confidence interval for a proportion in order to build the desired 95% confidence interval?
Explanation / Answer
Why can we not use the large-sample formula for confidence interval for a proportion in order to build the desired 95% confidence interval?
the reason that we cant use the large sample formula for confidence interval for a proportion is that the sample size in this case is 20 , the minimum sample size to use the large sample formula for confidence interval is 30