In: Math
A car company claims to only have a carbon dioxide emissions of .7. You think it’s higher. You collect 100 cars and test the carbon dioxide. You find an average of .75 with a sample standard deviation of .1. Perform a test of hypothesis with an alpha of 10%.
Ho : µ = 0.7
Ha : µ > 0.7
(Right tail test)
Level of Significance , α =
0.10
sample std dev , s = 0.1000
Sample Size , n = 100
Sample Mean, x̅ = 0.7500
degree of freedom= DF=n-1= 99
Standard Error , SE = s/√n = 0.1000 / √
100 = 0.0100
t-test statistic= (x̅ - µ )/SE = ( 0.750
- 0.7 ) / 0.010
= 5.000
p-Value = 0.0000 [Excel formula
=t.dist(t-stat,df) ]
Decision: p-value<α, Reject null hypothesis
Conclusion: There is enough evidence to reject the company's claim
at α=0.10.