A certain soft drink bottler claims that at most 10% of its customers drink another brand of soft drink on a regular basis. A random sample of 100 customers yielded 18 who did in fact drink another...

A certain soft drink bottler claims that at most 10% of its customers drink another brand of soft drink on a regular basis. A random sample of 100 customers yielded 18 who did in fact drink another brand of soft drink on a regular basis. Do these sample results contradict the bottler’s claim? (Use a level of significance of 0.05.)