(07. 04 LC)


Mellie is conducting a test on mold spores on bread. She uses 6 slices of bread to compare two strains of mold. She applies one strain to the left side of the bread and one strain to the right side. She flips a coin to decide which strain goes on the right side of the bread. The mold spores that appear on each side are counted and she records them in a table.


Bread Number of Spots for Strain 1 Number of Spots for Strain 2

1 30 19

2 21 17

3 15 15

4 13 12

5 6 9

6 8 4

If Mellie is to perform an appropriate t-test to determine if there is a mean difference between the number of spots per piece of bread produced by the two strains, how many degrees of freedom should she use?


a

4


b

5


c

6


d

10


e

12