Answer:
0.00135
Step-by-step explanation:
Given that a textile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms.
H0: µ = 12 against H1: µ < 12
n =4
std error = [tex]\frac{0.5}{\sqrt{4} } =0.25[/tex]
Mean difference [tex]= 11.25 -12 = -0.75[/tex]
Test statistic t = mean diff/std error = -3
p value=0.00135 <0.05 our significance level
So reject H0
There is evidence to prove that mean is less than 12 kg.
