I attached a photo that explains and gives the answer to your questions. Had to add a border because the whole picture didn’t fit.
Answer: It means "Do it yourself".
Explanation: You're welcome!
Answer:
Why do you want to know...?
Answer:
b) The null hypothesis should be rejected.
Explanation:
The null hypothesis is that the mean shear strength of spot welds is at least
3.1 MPa
H0: u ≥3.1 MPa against the claim Ha: u< 3.1 MPa
The alternate hypothesis is that the mean shear strength of spot welds is less than 3.1 MPa.
This is one tailed test
The critical region Z(0.05) < ± 1.645
The Sample mean= x`= 3.07
The number of welds= n= 15
Standard Deviation= s= 0.069
Applying z test
z= x`-u/s/√n
z= 3.07-3.1/0.069/√15
z= -0.03/0.0178
z= -1.68
As the calculated z= -1.68 falls in the critical region Z(0.05) < ± 1.645 the null hypothesis is rejected and the alternate hypothesis is accepted that the mean shear strength of spot welds is less than 3.1 MPa
Answer:
The surface area of the primary settling tank is 0.0095 m^2.
The effective theoretical detention time is 0.05 s.
Explanation:
The surface area of the tank is calculated by dividing the volumetric flow rate by the overflow rate.
Volumetric flow rate = 0.570 m^3/s
Overflow rate = 60 m/s
Surface area = 0.570 m^3/s ÷ 60 m/s = 0.0095 m^2
Detention time is calculated by dividing the volume of the tank by the its volumetric flow rate
Volume of the tank = surface area × depth = 0.0095 m^2 × 3 m = 0.0285 m^3
Detention time = 0.0285 m^3 ÷ 0.570 m^3/s = 0.05 s
