Mastery Check – Introduction to Statistics

You collect data on the number of plants in 3 meter by 3 meter plots. You find a mean of 100 plants per plot with a standard deviation of 10. Which of these ranges will capture ~68% of your data?

When a distribution of data has a high standard deviation, what can we expect? Select all that apply

What does hypothesis testing allow us to do?

You are testing a synthesized medicine against a control sample. Specifically, you are measuring cortisol levels after administrating the medicine. Your pharmaceutical company uses elevated cortisol levels as a metric for stress (a negative side effect). In order to come to market, your medicine cannot cause a significantly different cortisol response compared to the control sample.  After running your experimental trials, you run a simple t.test to see if there is a difference in cortisol levels between the treatment and control groups.  You receive a p-value of .7 and a Cohen’s D of .2.

How would you interpret these results in the context of this study?

You are counting the number of individual gophers over 100 study plots. You decide to create a quick probability distribution using the counts of plots with a particular number of gophers. These are your results:

• 1 gopher – 7 plots
• 2 gophers – 3 plots
• 3 gophers – 10 plots
• 4 gophers – 25 plots
• 5 gophers – 30 plots
• 6 gophers – 15 plots
• 7 gophers – 15 plots
• 8 gophers – 5 plots

Using this list, what is the percent probability of counting 5 gophers if we sample a site at random?

Your boss was so impressed with your work, they asked you to keep counting gophers at a new study site!

Here are new counts for the number of individual gophers over 100 study plots. You decide to create a quick probability distribution using the counts of plots with a particular number of gophers. These are your results:

• 1 gopher – 20 plots
• 2 gophers – 10 plots
• 3 gophers – 15 plots
• 4 gophers – 25 plots
• 5 gophers – 15 plots
• 6 gophers – 5 plots
• 7 gophers – 5 plots
• 8 gophers – 5 plots

Using this list, what is the percent probability of counting 4, 5, or 6 gophers if we sample a site at random?

Your boss was so impressed with your gophering abilities, they have appointed you Lead gopherologist, a highly coveted position in your department. 

They have a landowner who is interested in purchasing one of the 2 properties you’ve sampled. They ask you which they should purchase based on Which property has a lower probability of having 4 or more gophers at a randomly sampled site?

Property A: 

• 1 gopher – 7 plots
• 2 gophers – 3 plots
• 3 gophers – 10 plots
• 4 gophers – 25 plots
• 5 gophers – 30 plots
• 6 gophers – 15 plots
• 7 gophers – 15 plots
• 8 gophers – 5 plots

Property B: 

• 1 gopher – 20 plots
• 2 gophers – 10 plots
• 3 gophers – 15 plots
• 4 gophers – 25 plots
• 5 gophers – 15 plots
• 6 gophers – 5 plots
• 7 gophers – 5 plots
• 8 gophers – 5 plots