The amount of paint used on new tractors averages 18.2 gallons with a standard deviation of 0.8 gallons. A new nozzle is used on 20 tractors and averaged 17.9 gallons. What is the probability that is was just random chance

17.9/18.2 =0.984 to 3 decimal places

Step-by-step explanation:

The initial mean/average = 18.2 gallons

A standard deviation of 0.8 gallons implies a lower-upper limit of (17.4 - 19) gallons of paint used on new tractors.

New mean/average = 17.9 gallons

It is noticeable that this value 17.9 falls within the lower range of the standard deviation of the initial mean; hence the question

What is the probability that this happened by chance?

17.9 ÷ 18.2 = 0.9835

Therefore, there is a high probability that this happened by chance. 0.9 is closer to 1 than to 0.