Question 1
1) How many plastic products do you think you use each week? How do you think this compares to your neighbors?
Credit: iStock/piotr_malczyk
In this in-class activity, you will be revisiting the “plastics” dataset used in In-Class Activity 13.A. Recall that this dataset is a sample of plastic products collected by community volunteers in countries around the world during a brand audit to see what types of plastics are found in waste and from which companies the plastics found came from.
The dataset can be accessed at https://docs.google.com/spreadsheets/d/15RIs8K9MaGVfYQmi15bH87dUIz8X1o60Wcs ukoLlFFo/edit?usp=sharing.
Question 2
2) In In-Class Activity 13.A, you used a subset of the “plastics” dataset that contains counts of plastics from The Coca-Cola Company in 2020.
a) What was the research question you were trying to answer using the Coca Cola subset of data?
b) What were the null and alternative hypotheses you wrote to answer the research question?
c) Is this a one-tailed or two-tailed one-sample test?
d) What is the sample mean count of all plastic products reported in 2020 that are from The Coca-Cola Company?
e) What is the sample standard deviation of all plastic products reported in 2020 from The Coca-Cola Company in the subset?
Question 3
3) Calculate the value of the test statistic by hand using the formula introduced in In Class Activity 12.B:
[latex]t=\frac{\bar{x}-\mu_{0}}{s/\sqrt{n}}[/latex]
Question 4
4) Let’s say that we got a new sample of the total plastics count for products from The Coca-Cola Company in the sample of countries around the world. Would the value of the test statistic that we calculated using this new sample change from the test statistic value we calculated in Question 3? Explain.
Question 5
5) Use the DCMP Inference for a Population Mean tool at
https://dcmathpathways.shinyapps.io/Inference_mean/ to calculate the P-value with a significance level of 0.05.
a) What is null value you entered into the data analysis tool?
b) What is the P-value?
c) Does the value of the test statistic from the data analysis tool match your answer to Question 3?
Question 6
6) How would you interpret the result of this test in context? Is there evidence to suggest that the claim by Coca-Cola is false?
The following is a list of companies that have a large enough sample size to meet the conditions for a hypothesis test:
| 2019 | 2020 |
| Nestle | Nestle |
| PepsiCo | PepsiCo |
| Unilever | |
| Mondelez International | |
| Mars, Incorporated |
Choose a company from the list. Create a subset of data for the company you chose by filtering by the parent_company variable and the year. This is the subset of data you will use to answer Questions 7–10.
In Questions 7–10, use a significance level of 0.05 and a hypothesized value of 90 items. The variable that you will be focused on is the total plastics count found in various countries.
Question 7
7) Which company did you choose?
Question 8
8) What is your research question? What are the null and alternative hypotheses?
Question 9
9) Calculate the test statistic and P-value using the DCMP Inference for a Population Mean tool.
Question 10
10) How would you interpret the result of the test in context?
