## Solved: Core Communication Assignment 3

**Introduction: **This assignment presents an example of using various functions to model a given data set, and then using that model to make predictions and come to conclusions about the given situation. Part of this process will involve using Microsoft Excel to graph a set of data and add “trendline” models to that graph. (See handout.) Your submission may be

typed or handwritten, and should be presentable, with all questions answered in the order given below.**Group Submission: **One of the communication aspects of this assignment is that students work collaboratively; this is a skill that is necessary for all aspects of life outside of this class, and so is crucial to your education as part of the core curriculum. As such, each group will make a single submission of this assignment, printed and with the names of the

contributing group members listed at the top of the first page. Any group member who does not significantly contribute to the submission should not be listed, and will receive a zero for the assignment.**Due Date:** Each group will make a single online submission on Blackboard, no later than 8:00pm on Friday, December 8th

. Any questions or concerns on your submission should be directed to the instructor before the end of the business day on Thursday, December 7 th

. Problem Statement: A strain of E-coli Beu 397-recA441 is placed into a nutrient broth at 30∘ Celsius and allowed to grow. The following data represent the growth of the bacteria over the first 6 hours after the bacteria was placed in the petri dish. The population is measured using an optical device in which the amount of light that passes through the petri dish is measured. The observations given for population denote the fraction of the petri dish that is covered by bacteria; for example, 30 minutes into the experiment, 9% of the dish is covered with bacteria.

Our first goal is to use Excel to chart this data and give an equation that best fits the data (called a model), through a process called regression. Don’t worry, Excel does all the heavy lifting in the background.

- Input the given data into Excel, and follow the handout (if needed) to chart the data in a basic scatter plot, adding appropriate axis and chart labels. Copy this chart into your submission document.
- Next, you’ll add “trendline” models to your chart, with the eventual goal of determining which of the following models best fits your data.

(a) Create a copy of your chart and add to it a linear trendline, with equation. Copy this chart into your submission document.

(b) Create another copy of your original chart and add to it an exponential trendline, with equation. Copy this chart into your submission document.

(c) Create another copy of your original chart and add to it a logarithmic trendline, with equation. Copy this chart into your submission document. - In 2-3 complete sentences, evaluate the models you generated in 2(a)-(c), and conclude, based on a comparison of your charts, which model best fits the data.
- Find and, in at least one complete sentence, accurately interpret the ?-intercept of the model you have chosen.
- Use your model to predict the bacteria population after 7 hours. Show your work, interpret your answer, and respond in the form of a complete sentence.
- Use your model to predict when the petri dish will be 80% covered by bacteria. Show your work, interpret your answer, and respond in the form of a complete sentence.
- Use your model to predict when the petri dish will be 100% covered by bacteria. Show your work, interpret your answer, and respond in the form of a complete sentence.
- In a well-written paragraph, consisting of 3-5 complete sentences, analyze your answer to question 7 above, by answering the following questions:
- Does your answer to question 7 seem reasonable?
- What realistic factors may negatively impact the suitability of the model you generated in this assignment?
- Is there another type of function/model that may better represent the growth of bacteria in a petri dish?
- (
*Hint: Look back at the models discussed in section 6.7.)* - If so, what makes this other type of function a better candidate for modeling bacteria growth?
- Your grade for this assignment will be based partly on demonstrating correct mathematical calculations, but just as important is the “communication” aspect of this communication assignment. That is, you must convey your results, both visually (through charts and graphs) and verbally (through complete sentences), in a way that is understandable to the reader and demonstrates your comprehension of the material. (Another important aspect of communication here is to ask if you need help!)