How to store value checked by checkbox ( on the VF page ) in the database with controller?

Sample Code:

Visualforce page:

<apex:page controller="Sample">
<apex:form >
    <apex:pageblock >
        <apex:pageBlockSection >
            <apex:panelGrid columns="2">
                Name :
                <apex:inputText value="{!Nam}"/>
                Skilled :
                <apex:inputCheckbox value="{!Skilled}"/>
        <apex:commandButton value="Save" action="{!sav}"/>

Apex Controller:

public class Sample { 
    public String Nam {get;set;}
    public Boolean Skilled {get;set;}
    Integer n = 5;
    public List<Member__c> MemList {get;set;}
    public Sample() {
    public void sav() {
        Member__c Mem = new Member__c();
        Mem.Name = Nam;
        Mem.Skilled__c = Skilled;
        insert Mem;