An online stock trading company makes part of their revenue from clients when the clients trade stocks therefore, it is important to the company to

An online stock trading company makes part of their revenue from clients when the clients trade stocks therefore, it is important to the company to have an good idea of how many trades its clients are making in a given year. In a sample of 85 clients of an online stock trading company, the average number of trades per year was 55 with a standard deviation of 23. Find the LOWER bound of the 95% confidence level of the average number of trades the company's clients make.