Reference no: EM131963824

Sludge is a dried product remaining from processed sewage and is often used as a fertilizer on agriculture crops. If the sludge contains a high concentration of certain heavy metals, such as nickel, the nickel may be at a concentration in the crops to be of danger to the consumer of the crop. A new method of processing sewage has been developed and an experiment is conducted to evaluate its effectiveness in removing heavy metals. Sewage of a known concentration of nickel is treated using both the new and old methods. One hundred tomato plants were randomly assigned to pots containing sewage sludge processed by one of the two methods. The tomatoes harvested from the plants were evaluated to determine if the nickel was at a toxic level. The results are as follows:

Level of Nickel

Treatment Toxic Non-toxic Total

New 5 45 50

Old 9 41 50

Total 14 86 100

Is there significant evidence (LaTeX: alpha=0.05α=0.05) that the new treatment would have a lower proportion of plants having a toxic level of nickel compared to the old treatment?