Descriptive Statistics and Data Visualization

MAT141 Assignment 1 Spring 2026 Descriptive Statistics and Making Graphs Basic Instructions This assignment is worth 5% of your final grade. Assignments must be uploaded as Word documents to TurnItIn via Classes, by the end of the day on Wednesday, Feb 18. In case you run in to technical difficulties, plan to submit it EARLY. See your instructor during her office hours or via Zoom appointment (Mon & Wed 4:30-6:00pm, Thu 3:00-5:00pm virtual) , Password: 123456), if you have any questions about the assignment. Make sure you submit your assignment in ONE file (either pdf or word), which includes the actual write-up for the assignment, both graphs you produced, and screenshot of your csv data file and screenshot of the R script that you used to complete your assignment. You could also use R markdown to complete your assignment. Assignment Objectives The goal of this assignment is to describe a sample, to estimate parameters of a population using the sample, and to visualize the data using graphs (histogram and boxplot). You will need to find or collect sampled data on your own. The data must be numerical, and must be a single variable (i.e., not comparing two groups). You could get the data from a book, from a website, or from an experiment you conducted yourself. Each student in the class must have her/his own data no data sharing! Your instructor recommends NOT using time as the unit of replication (i.e., each data point should not specifically be from a different time period it should be from a different individual person/animal/tree or place place including a hospital, petri dish, soil specimen, etc.). Remember too, that if you are estimating the frequency of occurrence in different places, it is typically more appropriate to convert these values to proportions (e.g., the proportion of people at each hospital that caught the flu, instead of the number of people at each hospital that caught the flu. This will control for the fact that there are a different number of people admitted to each hospital.) You are to do all calculations in R, and also create the graphs using R. Save your graphs and open them in a Word document, or copy and paste graphs into a Word document that also contains your written answers. Avoid using screen shots. Plagiarized work will results in a grade of ZERO for the entire assignment. Plagiarizing content on more than one assignment will result in an F in the course. Assignment Components Title: A short (one sentence) description of your study. (1 point) Introduction: Explain the goal of your study. What is the purpose of conducting the study? (1 point) What population are you trying to describe using a sample? (e.g., is it a population of hospitals in NYC?) (1 point) Methods: Describe, in words, how the sample data were collected from a population, including the sample size and the units (1 point). Explain what descriptive and inferential statistics you will use to describe the sample (Chapters 3 and 4 of your textbook) and state that you will use R calculate these statistics (1 point). Results: Write one sentence briefly describing your results, and include units in this sentence. In a table, present the mean, median, upper and lower quartiles, standard deviation, standard error, and approximate 95% confidence interval (5 points). Present a frequency histogram displaying the data (4 points). Present a boxplot displaying the data (4 points). ALWAYS label figure axes properly. ALWAYS include figure captions (at the bottom of the figure) describing what the figure represents, including the sample size in the caption. ALWAYS include table captions (at the top of the table) describing what the table represents, including the sample size in the caption. ALWAYS include units in figures and tables (captions, axes, column headers). Failure to do any of the above bullet-point steps will result in deducted points. Discussion: State your conclusion about the population, based on your statistics (and specifically based on your 95% confidence interval) (1 point). Referring back to the classes on sampling methods, do you think that you accurately and precisely estimated the mean of the population, or do you think there was bias or sampling error? (0.5 points for discussing bias and 0.5 points for discussing sampling error) HINT! Remember that if you repeated the experiment many times, you expect your sample mean to fall within the 95% confidence interval 95% of the time. Example notes and feedback to previous students: You should mention the version of R and R-studio softwares you used. For example: “R-studio Version 2024.12.0+467 (2024.12.0+467) was used to analyze the statistics”. I don’t see your raw data and r script, so I can’t tell whether you reported the correct numbers. Standard deviation of mean is one of the inferential statistics. What descriptive and inferential statistics did you use to describe the sample?