Answer:
a)
Hโ : ยตd = 0 ย
Hโ : ยตd < 0 ย
b)
The test statistic is
tโโโ = ฮฑ / sโn
c)
at 0.10 level of significance,
tโโโ , โ
tโโโโ , โ.โโ = tโโ, โ.โโ = 1.311
d)
given that ย T(critical) = 1.62
โด T(critical) = 1.62 > tโโ, โ.โโ = 1.311
at 10% level of significance,
REJECT Hโ
Since 1.62 > 1.311, we can reject the null hypothesis.