By formula we know that:
z (x) = (x - m) / [sd / sqrt (n)]
where x is the value we want to know (6.7), m is the mean (5), sd is the standard deviation (7.1) and n is the sample size (29).
Replacing we have:
z (6.7) = (6.7 - 5) / [7.1 / sqrt (29)]
z = 1.289
If we look in the normal distribution table (attached), we have that the probability is 0.8997, therefore:
1 - 0.8897 = 0.1003
So the conditional probability of a herd sample earning at least 6.7 pounds per steer is 10.03%.
Now the hypothesis tells me:
m> 5
The probability is somewhat low, therefore, the most correct thing is to reject the hypothesis even though it is a fact that can occur.
