# Common Core: High School - Statistics and Probability : Compare Two Treatments from Randomized Experiment: CCSS.Math.Content.HSS-IC.B.5

## Example Questions

### Example Question #1 : Compare Two Treatments From Randomized Experiment: Ccss.Math.Content.Hss Ic.B.5

A group of scientists studied the effects of hormone treatments on plant germination. They decided to study Zea mays or corn. They hypothesize that abscisic acid will inhibit plant growth, while gibberellins will counteract this germination inhibition. Scientists leave some seeds unaltered (i.e. the control group) and treat one group of seeds with abscisic acid, while a third group is treated with both abscisic acid and gibberellins. They continue these treatments for fourteen days and monitored the plant's growth. The data of this study is located in the provided figure.

Was there an observable difference between treatments in the study?

No, abscisic acid promotes plant growth and gibberellins can counteract growth promotion

Yes, gibberellins can counteract abscisic acid inhibition

Yes, abscisic acid promotes plant growth

Yes, abscisic acid inhibits plant growth and gibberellins can counteract growth inhibition

No, abscisic acid inhibits plant growth

Yes, abscisic acid inhibits plant growth and gibberellins can counteract growth inhibition

Explanation:

In order to solve this problem, let's first observe the steps associated with the scientific method. In this particular experiment we can see that the scientists have interest in a particular biological phenomenon: the effects of hormones on plant growth and germination. They develop a hypothesis based on these observations. A hypothesis is a tentative explanation for an observed phenomenon. In this experiment the scientists developed the following hypothesis: abscisic acid will inhibit plant growth, while gibberellins will counteract this germination inhibition. A null hypothesis is a statement of no difference. In other words, plant hormones will have no effect on plant growth.

In order to support or refute this hypothesis, the scientists developed a simulation or experiment. In this scenario, they exposed corn seeds to differing hormone treatments:

1. No treatment
2. Abscisic acid
3. Gibberellins and abscisic acid

They monitored the seeds for fourteen days and created a box plot using the data.

Let's look at how box plots are used to analyze data.

Box plots are broken into five main parts that create four primary regions. Each region contains a quarter of the data in the plot. The plot is initially broken into two regions using the following values: the minimum value, the maximum value, and the median or average of the set. Next, the minimum and median values are divided by the median of the lower half of the data or the first/lower quartile. Likewise, the median and the maximum values are divided by the median of the upper half of the data set or third/upper quartile. If the box is bigger, then there is a greater variance or spread in the data. Also, if the whiskers are very long, then the data possesses outliers.

When data is analyzed in a box plot or chart, it can then be used to make conclusions on the experiment. These conclusions will either support or refute a hypothesis. It is important to note that hypothesis cannot be proven support can only be added for them or against them. Even scientific theories such as gravity are not proven: they are just supported by a wealth of experiments and knowledge.

This brings us to the basis of this question. We need to make a conclusion based on the results of a simulation. Initially, we can see that the treatments had some effect due to the differences between the abscisic acid plot and the control plot; therefore, any choice that said there was not an effect can be disregarded. In the graph, we can clearly see that abscisic acid inhibits plant growth compared to the control; therefore, we can say, "abscisic acid inhibits plant growth." When we compare the control group with the treatment group that received both gibberellins and abscisic acid, we can see that they are comparable. This means that we can infer the following: "gibberellins can counteract abscisic acid inhibition." The correct choice is: "Yes, abscisic acid inhibits plant growth and gibberellins can counteract growth inhibition."