Question

A random sample of engines treated with Tag Full Treatment is given (sample std.dev =7.63)

Treated with TAG

130

135

131

142

127

121

Does this data support the claim that the secret additive has increased the horse power to more than 135 horse power.Use a 5% level of significance .

A. Determine H1

B. Answer the question

Answer 1

n =6

sample mean =

S =7.63

claim : The secret additive has increased the horse power to more than 135 horse power.

Null and alternative hypothesis is

H0 : u = 135

H1 : u > 135

Level of significance = 0.05

A. H1 : u > 135

B)

Here population standard deviation is not known so we use t-test statistic.

Test statistic is

Degrees of freedom = n - 1 = 6-1=5

P-value = 0.1277 ( using t table)

P-value , Failed to Reject H0

conclusion : There is insufficient evidence to support the claim that the secret additive has increased the horse power to more than 135 horse power