I started studying for an MBA degree and I was told it would be helpful to study Statistics.So I did. And now I am stuck

Summation(i=1,n) (Oi - Ei) squared divided by Ei

I need to use this formula to work out the frequencies expected under the hypothesis that the number of absentees is independant of the day of the week Below is the number of employees absent for a single day during a particular period of time

MOn(121absent), Tues (87absent) Weds (87 absent) Thur (91 absent) Fri (114 absent) TOTAL 500

Then I have to "test at the 5% level whether the differences in the observed and expected data are significant.

I want to be really dense and say "Eh??"

Please help somebody!! <Sob!>