Use a standard normal table to find the positive critical value that corresponds to a right tail area of 0.0250.025 , rounding to three decimal places

Let the require value be x, then

P (z > x) = 0.025

1 - P (z < x) = 0.025

P (z < x) = 1 - 0.025 = 0.975

P (z < x) = P (z < 1.96)

x = 1.96

Therefore, the positive critical value that corresponds to a right tail area of 0.025 is 1.96