For each of the following sets of information, find: 

i. The number of degrees of freedom 

ii. The critical value. 

a. Number of E_i cells after combining = 9. The data are believed to fit a normal distribution with mean 6. Test at 5% significance.

b. Number of E_i cells after combining = 7. The data are believed to fit a normal distribution. Test at 10% significance.

c. Number of E; cells after combining = 11. The data are believed to fit a normal distribution with mean 6 and variance 4.

Test at 2.5% significance.

d. Number of E_i cells after combining = 15. The data are believed to fit a normal distribution with variance 5.

Test at 5% significance.