Gather your statistics. Your university or college library probably includes a collection of recent medical journals. Researchers often publish their findings in such journals. You will be able to locate a name and an institution that will enable you to request further information. Also, look for findings from hearing aid companies as well as charitable organizations dedicated to the deaf. Many of these also produce statistics on hearing loss.
Consolidate your statistics. This means if you have researched your statistics from different journals, studies, companies and charities put them together in a manner that enables you to understand the results as a whole.
Break the statistics down into their core components for further study. This will give you a broader picture of trends within certain groups. For example, you can break them down based on gender, region, age groups, ethnic groups and so on. This, of course, depends on the level of data included in the statistics available to you. You may also break them down into the type of hearing test used or the technology used during the hearing test.
Map the trends that become apparent as you review the statistics. Are some groups affected more than others? Have there been discernible changes over the time span of the studies?
Look at the possible causes that may be responsible for the changes. Are there possible environmental or genetic issues that may explain the differing trends? Frame these possible causes and trends against your proposition in the introduction to your dissertation. Analyze the results and arrive at a logical conclusion that will be included in your work.
Illustrate your statistics using a variety of methods that make the information readily accessable to the reader. These can include tables, graphs and pie charts or a combination of any of these.
Acknowledge the faults of your work and of the statistics during the analysis. This will demonstrate an awareness of the work's limitations and is essential to producing a balanced and intellectually honest dissertation.