I am not understanding the z table can someone explain? That's where I get stuck.

A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 248.4cm and a standard deviation of 0.7-cm. A steel rod is chosen at random from all those produced by the company. What is the probability that the length of this rod is greater than 248.2 cm. :l Enter your answer as a number accurate to 4 decimal places. Answers obtained using exact zscores or z-scores rounded to 3 decimal places are accepted