A new program has been proposed in the elementary school system to introduce 8- and 9-year-old students to the study of science. A random sample of 30 students was selected and divided at random into two groups. One group consisting of 12 students was assigned to the new program, while the other 18 students were taught in the traditional manner. Fewer students were assigned to the new program because it is a more expensive program to teach. At the end of the school year a standardized test is administered to the students and their scores compared. The following is a summary of the results of the final test scores: New Program Traditional Program Number of Students 12 18 Sample Mean 78.2 73.8 Sample Standard Deviation 5.2 6.8 It is not unreasonable to assume that the population standard deviations, although unknown in value, are equal, i.e. ON Or . Using the summary statistics in the table above, what would be the pooled estimate of the common standard deviation o? O A) 11(5.2) +17(6.8)2 1 1 12 +18-2 12 18. O 11(5.2) +17(6.8)2 B) 12 + 18 -2 O C) (5.2)2 (6.8)2 12 18 O D) 11(52) +17(6.8) 12 + 18-2 O