capturing radio button values for nested object

I have a user object and an account object. User has one account object. In the signup.rhtml I have a radio button that has three options for the membership (yearly, monthly and sample). How do I populate the account model when the user submits the form? Is the following syntax correct?

<%= radio_button("user[account]", "membership", "Yearly") %> Yearly<br> <%= radio_button("user[account]", "membership", "Monthly") %> Monthly<br> <%= radio_button("user[account]", "membership", "Sample") %> Sample<br>

TIA