1. An economist has measured the incomes of a population. The average income is unknown, however the standard deviation of the incomes is $4000. A) the economist considers a sample of 100 incomes from the population. With 90% confidence compute the maximum error between the average income of the sample and the true mean income of the population. B) with 90% confidence compute the minimum sample size of a sample so that error between the average of the sample and the mean of the population is $1000. 2. True or false: as the sample size increases, while all other parameters remain the same, the length of the confidence interval for the mean decreases. 3. A surveyor has found an old collection of data and statistics about heights of building in a city. The sample average of a collection of 64 buildings heights, from a particular neighborhood, is 80ft and the sample standard deviation of the heights of the 64 buildings is 24ft given this information a) determine the 90% confidence interval for true average of the heights from the data set. B) determine the 95% confidence interval for the true average of the heights from the data set.
1) a) Maximum error between the average income of the sample and the true mean income of the population = $658 b)... View the full answer