At wind speed above 1000 cm/sec, significant sand-moving events begin to occur. Wind speeds below 1000 cm/sec deposit sand, and wind speeds above 1000 cm/sec move sand to new locations. The cycling nature of wind and moving sand determines the shape and location of large sand dunes. At a test site, the prevailing direction of the wind did not change noticeably. However, the velocity did change. Sixty wind speed readings gave an average velocity of cm/sec. based on long-term experience,s can be assumed to be 265 cm/sec.

1. What is the margin of error for this interval? Show calculation.