Problem 4: To measure water clarity in a lake, a glass plate with ruled lines is
ID: 3310766 • Letter: P
Question
Problem 4:
To measure water clarity in a lake, a glass plate with ruled lines is pushed down into the water until the lines cannot be seen anymore. The distance below the surface of the water is called "Secchi depth." To measure pollution by algae, scientists determine the total concentration of chlorophyll in the water. In a certain lake, Secchi depth and total chlorophyll concentration are measured every Thursday at noon from April through September. Will the correlation between these variables be positive or negative? Explain briefly.
Explanation / Answer
Water in a lake is clean when there is no algae or other water plant
Since
Line on glass cannot seen when there is sufficient amount of algae or other plants available at that depth I.e.secchi depth
So
Here secchi depth is depth at which sufficient amount of algae or other plants that makes impossible to see the lines on glass plate
While as every plant contain clorophyll in leafs so amount of chlorophyll depends on amount of algae or other plants in Water
So if concentration of chlorophyll is less so less algae so secchi depth is more
While if concentration of chlorophyll is high then high amount of algae hence secchi depth is less
Hence there is negative correlation b/w both