A cheese manufacturer is seeking to determine whether two different kinds of packaging of a certain kind of cheese differ in their ability to protect cheese from mould. To do so, 20 equal-sized pieces of cheese are cut from one randomly selected block, 10 are packaged by Method A and 10 are packaged by Method B. At 10 different locations, one Method A pack and one Method B pack are left until mould appears. The results (in days) before mould appears are provided in the file Question3.xls.

a) Use Excel to test whether there is a difference, at the 5% significance level, between the abilities of the two different kinds of packaging to protect the cheese from mould. [6 marks]

question3 xls

A	B
17	10
23	18
9	10
12	8
25	17
18	18
6	4
21	10
14	15
11	5

b) Prior to the above analysis, a manufacturing employee had commented that, based on his knowledge of cheese packaging, the difference in mean days for mould to appear would surely not be more than one day. Explain, using support from a hypothesis test performed at the 5% significance level, what you would conclude about his comment. [4 marks]