A distance was measured by pacing as 267 ft. with a standard deviation of ±3 ft. It was then measured as 269.08 ft. with a steel tape and had a standard deviation of +0.05ft. Finally, it was measured as 268.99 ft. with an EDM instrument. The EDM instrument and reflector setup standard deviations were ±0.005 ft and ±0.01ft. respectively, and the manufacturer's estimated standard deviation for the EDM instrument is ±( 5 mm + 5 ppm). What are the most probable value for the distance and its standard deviation? What is the computed standard deviation for each weighted observation?