populating cell with specific value if text from drop down list in in another cell =

How do i write a formula to populate say b1 with a particular value if a1 has a particular text from a drop down list? My drop down list in a1 would be

Bed Rest
Very Sedentary
Sedentary/Maintenance
Light
Light Moderate
Moderate
Heavy
Very Heavy

Each one has a corresponding value (listed below in order)

1.2
1.3
1.4
1.5
1.7
1.8
2.1
2.3

How would I create a formula that would populate b1 with the value that corresponds to the choice from the drop down list?

Thanks in advance