Answer:
a.
H₀:β=0
H₁:β≠0
b.
p-value: 0.2935
95% CI: [-45.91;19.71]
Explanation:
Hello!
You need to make a linear regression test. For this, you have two variables
X: Operators
Y: Wait time
x: 4 ; 5; 6; 7 ; 8
y: 385 ; 335 ; 383 ; 344 ; 288
The linear regression equation:
Yi: α + βxi + εi
a. The Hypothesis for a two-tailed test for the slope is:
H₀:β=0
H₁:β≠0
b.
The statistic is
t= (b-β)/√Sb₂ ~

I've used a statistic software to calculate the values
b= 10.31
= -1.27
p-value= 0.2935
The 95% CI for the slope, using the formula:
b±
*Sb
is,
[-45.91;19.71]
I hope you have a SUPER day!