Lab Assignment 1

library(readxl)
library(mosaic)

1. Identify the population and the sample in this scenario.

The population is the set of all cereals in this scenario

The sample is the cereals at the nutritionists particular local grocery store

---

2. Consider the variables in the data set. Identify the variables that are qualitative and those that are quantitative.

$ Shelf Qualitative $ Name Qualitative $ Manufacturer Qualitative $ Type Qualitative $ Calories Quantitative $ Protein Quantitative $ Fat Quantitative $ Sodium Quantitative $ Fiber Quantitative $ Carbohydrates Quantitative $ Sugars Quantitative $ Potassium Quantitative $ Vitamins Quantitative $ Weight (of One Serving Cup) Quantitative $ Cups in Serving Quantitative

---

3. Consider the variable Shelf. This variable is the shelf position of the cereal (bottom, middle, top) starting from the floor up.

To see whether the shelf position is associated with one measure of nutritive value, the amount of sugar, look at the data for the variable Sugars. Compare the sugar content of cereals on each shelf by making a separate histogram for the sugar content of the cereals on each shelf: a total of three histograms. Use the sugar content values as they are - do not factor in the serving size. (The data for one of the cereals, Quaker Oatmeal, is missing. Just continue with what is available. That’s the way it is in real life - values are missing, files are incomplete, etc.)

• Use the same scales for your histograms so you can compare the data easily.
• Title each histogram and label the axes.

hist(Cereal_Data\(Sugars[Cereal_Data\)Shelf==“Top”])

hist(Cereal_Data\(Sugars[Cereal_Data\)Shelf==“Bottom”])

hist(Cereal_Data\(Sugars[Cereal_Data\)Shelf==“Middle”])

i

e

e

i

e

e

i

i

e

e

i

e

e

i

i

e

e

i

e

e

i

i

e

e

i

e

e

i

e

i

i

e

e

i

e

e

i

---

4. Briefly describe the distribution in each histogram with respect to shape. Based on your histograms, which shelf position has cereals with the most sugar?

The histogram for the top shelf is Bell shaped or symmetric

The histogram for the middle shelf is a left skewed histogram

The histogram for the bottom shelf is a right skewed histogram

Based on the histograms and the frequency that high amounts of sugar is associated with each cereal, I feel as though the top shelf contains the most sugar.

---

5. (Bonus Question) Consider your histograms for sugar content. Is the shelf position of a cereal related to its nutritive value as measured by sugar content? Can you provide a possible explanation for this relation?

No, the shelf position of a cereal is not related to its nutritive value as measured by sugar content.

Because all shelves of cereal have a large range of sugar content and is, therefore, does not determine the nuritional value. The top shelf ranges from 3-8g, the middle shelf ranges from 1-7g, and the bottom shelf ranges from 0-6g. Yes, it is possible to grab a cereal of the top shelf with 8g of sugar in it but this is only one cereal compared to the rest on the shelf it has a wide range and can’t determine the nutritional value.

---

6. Find the five-number-summary, mean, and standard deviation of the variable “Fiber”.

Five-Number Summary: 0, 0.5, 2, 3, 14

Mean: 2.152

Standard Deviation: 2.383

---

7. Draw side-by-side boxplots for the fiber content for each of the three groups: cereals on top shelf, cereal on middle shelf, and cereals on bottom shelf. Can you tell from the boxplots which group has the largest standard deviation?

i

e

e

i

e

e

i

i

e

e

i

e

e

i

i

e

e

i

e

e

i

i

e

e

i

e

e

i

e

i

i

e

e

i

e

e

i

---

8.Are Calories and Carbohydrates related in cereals? Let’s find out by studying the linear regression between the two variables.

---