A study compared floral diversity between croplands and wetlands. Independent random samples of 120 cropland regions and 61 wetland regions were obtained in the Southern Great Plains. The cropland regions contained an average of 15.03 native floral species, with a standard deviation of 4.83; the wetland regions had an average of 16.76 and a standard deviation of 4.95.

(a) Test if the mean number of native floral species is lower in cropland regions. Use the 1% significance level.

(b) Obtain a two-sided 99% confidence interval for the difference in mean number of floral species between cropland and wetland regions.