Answer:
(a) Null Hypothesis (H₀) = Mean of x₁ > Mean of x₂
Alternative Hypothesis (H₁) = Mean of x₁ ≠ Mean of x₂
(b) We will use here t-test for two sample means which is given by,
[tex][tex]t = \frac{\bar_{x_{1}}-\bar_{x_{2}}}{\sqrt{s^2(\frac{1}{n_{1}}+\frac{1}{n_{2}} )}}[/tex][/tex]
Putting all values we get, t = 17.5 with 20 degree of freedom
At α = 0.05
p-value = 95% Confidence Interval for the Difference ( 6.6068 , 8.3932 )