According to a study carried out by an industrial hygiene organization on 300 workers in the Outaouais workers in the Outaouais region exposed to significant noise, the average sound level required to detect a 10 kHz signal was 32 db with a standard deviation of s = 28. standard deviation s = 28. The union for these workers states that there are 2000 workers who are members of their union. Determine the upper limit for an 80% confidence interval for u, the average sound level required for all individuals who are exposed to this type of Noise.

a) 33,91 b) 34,45 c) 35,84 d) 34,92 e) 34,15