The standard error of the mean is 128.125.
The formula for standard error is:

With our information, we have:
Both distances 3966 and 4746 were done in 6 hours, so the speeds are:
speed against wind = 3966/6=661 km/h (difference of airplane and wind)
speed with wind = 4746/6=791 km/h (sum of airplane and wind)
The speed of airplane is greater than that of the wind, so this is a sum and difference problem.
Greater speed (plane) = (sum+difference)/2=(791+661)/2=726 km/h
Lesser speed (wind) = (sum-difference)/2 = (791-661)/2 = 65 km/h
In order to do this, we would use order of operations. First, Parentheses, which is division with fractions, so we would do KCF,keep it, change it, flip it. keep the first fraction, change the operation to multiplication, then flip the next fraction, making it -7/9 x 3/1. the answer would be -2.33. multiply that by -2, and you would get -4.66, which is your answer. PLEASE MARK BRAINLIEST IF HELPFUL! :))