The modulus of rupture (MOR) for a particular grade of pencil lead is known to have a standard deviation of 250 psi. Process standards call for a target value of 6500 psi for the true mean MOR. For each batch, an inspector tests a random sample of 16 leads. Management wishes to detect any change in the true mean MOR. (Assume normal distribution.)
QUESTION : Find the probability of type II error of the test when the true mean MOR is 6400.
How do we solve for two tails? i am able to get 0.4821 but with 1 tail method. 6397-6400/62.5 = 0.045 than using normcdf on MATLAB, i got this value