Industrial wastes and sewage dumped into our rivers and streams absorb oxygen and thereby reduce the amount of dissolved oxygen available for fish and other forms of aquatic life. One state agency requires a minimum of 5 parts per million of dissolved oxygen in order that the oxygen content be sufficient to support aquatic life. Six water specimens taken from a river at a specific location during the low-water season gave readings of 4.9, 5.1, 4.9, 5.0, 5.0, and 4.7 parts per million (ppm) of dissolved oxygen. Do the data provide sufficient evidence to indicate that the dissolved oxygen content is less than 5 ppm? Test using the a= 0.05 significance level.