When women take birth control pills, some of the hormones found in the pills eventually make their way into lakes and waterways. In one study, a water sample was taken from various lakes. The data indicate that as the concentration of estrogen in the lake water goes up, the fertility level of fish in the lake goes down. The estrogen level is measured in parts per trillion (ppt) and the fertility level is recorded as the percent of eggs fertilized.a. What are the cases in this study?b. How many variables are mentioned in the description?c. What are the variables?d. Classify each variable as either qualitative or quantitative.

A water sample was taken from various lakes. The data indicate that as the concentration of estrogen in the lake water goes up, the fertility level of fish in the lake goes down.

The estrogen level is measured in parts per trillion (ppt) and the fertility level is recorded as the percent of eggs fertilized.

a) Case in study

The case in study is to find the effect on estrogen level on fertility level in fish.

As the estrogen level increases, the fertility level in fish decreases.

b) Variables in description.

There are two variables.

The estrogen level
Fertility level

d) Types of variable

The estrogen level is measured in parts per trillion (ppt) and the fertility level is recorded as the percent of eggs fertilized. thus, both are expressed in numerical values. Thus, they are a quantitative variables.

Also, both the estrogen level and fertility level are measured and not counted. Both can take any value within an interval and can be expressed in decimals. Thus, they bot are continuous variable.