# Thread: What does the data suggest?

1. ## What does the data suggest?

A larger orchard has averaged 140 pounds of apples per tree per year. A new fertilizer is tested to try to increase yield. Forty trees are randomly selected, and the mean and standard deviation of the yield are sample mean ( x bar) = 143.2 and s = 9.4. Do the data indicate a significant increase in yield?

2. Originally Posted by bombo31
A larger orchard has averaged 140 pounds of apples per tree per year. A new fertilizer is tested to try to increase yield. Forty trees are randomly selected, and the mean and standard deviation of the yield are sample mean ( x bar) = 143.2 and s = 9.4. Do the data indicate a significant increase in yield?
As with the other problem compute the t-score or z-score for the sample mean:

$\displaystyle t=\sqrt{40}\frac{143.2-140}{9.4}\approx 2.153$,

Looking this up we see that a difference this large or larger will occur with
a probability of less than 3%, so at this level we may conclude that there
is a significant increase in yeild.

RonL