I have ubuntu 14.04 and when I want to connect to the wifi my network manager found nothing and when I use this command

sudo iwlist wlan0 scan

It can find my essid wifi and when I use this command to connect

sudo iwconfig wlan0 essid "sample"

Nothing happen and I can't connect neither my ifconfig command show this

eth0      Link encap:Ethernet  HWaddr b8:88:e3:0e:03:49  

          UP BROADCAST MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:0

          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

          Interrupt:16 



lo        Link encap:Local Loopback  

          inet addr:127.0.0.1  Mask:255.0.0.0

          inet6 addr: ::1/128 Scope:Host

          UP LOOPBACK RUNNING  MTU:65536  Metric:1

          RX packets:1576 errors:0 dropped:0 overruns:0 frame:0

          TX packets:1576 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:131573 (131.5 KB)  TX bytes:131573 (131.5 KB)



wlan0     Link encap:Ethernet  HWaddr 08:ed:b9:fa:1f:3b  

          inet6 addr: fe80::aed:b9ff:fefa:1f3b/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:29

          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

          Interrupt:17 

My wifi device is broadcome :

03:00.0 Network controller: Broadcom Corporation BCM43228 802.11a/b/g/n  

This is the text file of that script for my wifi information

Text File Contain My Wireless info

What should I do to connect to the wifi??