Porosity measurements in several oil fields show a normal distribution with a mean of 5% and a standard deviation of 1%. A total of 25 measurements are collected randomly from the available data. Determine the minimum value of the mean of porosity for such a sample so that the probability to have it lower than it is 5%.

Select one:

a. 4.67

b. 3.36

c. 4.75

d. 4.61

Select one:

a. 4.67

b. 3.36

c. 4.75

d. 4.61