for the online arrivals example, what is the standard error if p=0.8 and n= 400?

Ontime Arrivals The Bureau of Transportation Statistics! tells us that 80% of flights for a particular airline arrive on time (defined as within 15 minutes of the scheduled arrival time). We examine a random sample of 400 flights for this airline and compute the proportion of the sample flights that arrive on time. Compute the standard error for this statistic and verify that the conditions to use a normal distribution apply. e n=400 and p=0.8 o np=400(0.8)=32010 o n(1p)=400 (0.2)=8010 e Mean = 0.8, S=v0.8(10.8)/400 =0.02