ruby on rails - NoMethodError in Researches#index -

i try make application on rails similar official tutorial http://guides.rubyonrails.org/getting_started.html, instead of articles, have used researches. where's fault if i, when try view list of research, receive error. mistake?

undefined method `name' nil:nilclass 

researchescontroller

class researchescontroller < applicationcontroller      def new   end    def show     @research = research.find(params[:id])         end      def index         @researches = research.all     end      def create     @research = research.new(research_params)      @research.save     redirect_to @research   end    private     def research_params     params.require(:research).permit(:name, :period_of_execution, :cost)   end end 

index.html.erb

<h1>listing of our researches</h1>  <table>   <tr>     <th>name:</th>     <th>period of execution:</th>     <th>cost:</th>   </tr>    <% @researches.each |research| %>     <tr>       <td><%= @research.name %></td>       <td><%= @research.period_of_execution %></td>       <td><%= @research.cost %></td>     </tr>   <% end %> </table> 

you have write:

<td><%= research.name %></td> <td><%= research.period_of_execution %></td> <td><%= research.cost %></td> 

because referencing variable declared here:

<% @researches.each |research| %>