Can someone let me know if this is correctly done?

At Happy Smile we keep track of Dentists. Each Dentist has a Family Name, Birthday, Date Licensed, and License Number. License Number is a combination of letters and numbers. We also have Instruments. Instrument is owned by only one Dentist. Each Dentist can own more than one Instrument. We maintain information like Name, Weight and Date Acquired for every Instrument. The database must store information about Conventions. Each Convention has a Name and an Address. Many Dentists may attend many different Conventions, and every Convention may have several Dentists attending. For every attendance there is a Convention Date. There are also Manufacturers which make exactly one Instrument. Likewise, every Instrument can be made by at most one Manufacturer. Each Manufacturer has a Name, Instrument Cost and a Date Manufactured.

Your task is to do the following:

1. Draw an Entity-Relationship Diagram based on the information in the interview. You can use any free online E/R diagram program you like. Be complete, labeling everything, all entities, relationships and mark primary keys at least.

Thank You!