A major airline company is concerned that its proportion of late arrivals has substantially increased in the past month. Historical data shows that on the average 18% of the company airplanes have arrived late. In a random sample of 1,240 airplanes, 270 airplanes have arrived late. If we are conducting a hypothesis test of a single proportion to determine if the proportion of late arrivals has increased using the following hypotheses $H_0: p = 0.18$ and $H_a: p > 0.18$
Step 1 of 3: What is the value of the test statistic? Round your answer to four decimal places.