41 	double mean;  in main()  local
81 	mean = sum_x / num_data_items;  in main()
82 	printf("\tMean %.4f\n", mean);  in main()
83 	std_dev = sqrt((sum_sq_x / num_data_items) - (mean * mean));  in main()
85 	       std_dev, (std_dev * 100.0) / mean);  in main()
86 	one_sd_low = mean - std_dev;  in main()
87 	one_sd_high = mean + std_dev;  in main()
88 	two_sd_low = mean - (2 * std_dev);  in main()
89 	two_sd_high = mean + (2 * std_dev);  in main()
90 	three_sd_low = mean - (3 * std_dev);  in main()
91 	three_sd_high = mean + (3 * std_dev);  in main()