Tree size measures as diameter at breast height (DBH) Data for longleaf pine trees in two parts of a tract of land are compared. Suppose that you are planning a study in which you will measure the diameters of longleaf pine trees. Assume that the standard deviation for both parts is 20 cm. Suppose that a difference in mean DBH of 10 cm or more would be important to detect. You will use a t statistic and a two-sided alternative for the comparison. Find the power if you randomly sample 20 trees from each area to be compared for a significance level of 5%. Do not use the normal approximation. You will need to find the non-centrality parameter, then use the appropriate t distribution to calculate your answer.

Design an er diagram for keeping track of information about votes taken in the u. s. house of representatives during the current two-year congressional session. the database needs to keep track of each u. s. state's name (e. g., texas', new york', california') and include the region of the state (whose domain is {northeast', midwest', southeast', southwest', west'}). each congress person in the house of representatives is described by his or her name, plus the district represented, the start date when the congressperson was first elected, and the political party to which he or she belongs (whose domain is {republican', democrat', 'independent', other'}). the database keeps track of each bill (i. e., proposed law), including the bill name, the date of vote on the bill, whether the bill passed or failed (whose domain is {yes', no'}), and the sponsor (the congressperson(s) who sponsored - that is, proposed - the bill). the database also keeps track of how each congressperson voted on each bill (domain of vote attribute is {yes', no', abstain', absent'}). additional information: