A product developer is investigating the tensile strength of a new synthetic fiber that will be used to make cloth for men’s shirts. Strength is usually affected by the percentage of cotton used in the blend of materials for the fiber. The engineer conducts a completely randomized experiment with five levels of cotton content and replicated the experiment five times. The data are shown in the following table.

Cotton Weight Percentage	Observations
15	7,	7,	15	,11,	9
20	12	,17	,12	,18,	18
25	14,	19,	19,	18,	18
30	19,	25,	22,	19,	23
35	7,	10,	11,	15,	11

Is there evidence to support the claim that cotton content affects the mean tensile strength? Use α = 0.05.

Use the Fisher LSD method to make comparisons between the pairs of means. What conclusions can you draw?