Computer Science
Grade 10
20 min
Data Science Project: Analyzing a Real-World Dataset
Apply data science techniques to analyze a real-world dataset and draw conclusions.
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1
Introduction & Learning Objectives
Learning Objectives
Define key data exploration terms like feature, record, mean, median, and mode.
Load a dataset (e.g., from a CSV file) into a data structure like a DataFrame.
Calculate basic descriptive statistics (mean, median, count) for numerical data columns.
Analyze categorical data by counting the frequency of unique values.
Identify the appropriate type of visualization (bar chart, histogram, scatter plot) for different data analysis questions.
Interpret the results of their initial data exploration to form a basic hypothesis.
Ever wondered which video game genre has sold the most copies worldwide, or what the average movie rating is on a streaming service? 🎮 Let's learn how to find those answers ourselves!
This lesson is your first step into the world of a...
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Key Concepts & Vocabulary
TermDefinitionExample
DatasetA structured collection of data, typically organized into a table with rows and columns.A spreadsheet file (like a CSV) containing information about video game sales, where each row is a different game and each column is a piece of information like 'Title', 'Genre', 'Platform', and 'Global_Sales'.
Feature (or Column)A single characteristic or attribute of the data being measured. It's a column in your dataset's table.In a video game dataset, 'Genre', 'Release_Year', and 'Publisher' are all features.
Record (or Row)A single entry or observation in the dataset, containing all the feature values for that one item. It's a row in your dataset's table.A single row representing...
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Core Syntax & Patterns
Calculating Descriptive Statistics
dataframe['column_name'].describe()
This is a common pattern in data analysis libraries (like Pandas in Python). It's a powerful shortcut to get a summary of a numerical column, including the count, mean, standard deviation, minimum, maximum, and quartile values all at once.
Counting Categorical Data
dataframe['column_name'].value_counts()
Use this pattern to analyze a categorical column. It counts the number of times each unique category appears and returns a list of categories and their frequencies, usually sorted from most to least common.
Selecting a Column
dataframe['column_name']
To perform any analysis on a specific feature, you first need to select that column of data from your main dataset...
4 more steps in this tutorial
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Challenging
You are tasked with determining if 'Action' games, the most frequent genre, also have higher-than-average sales. Which sequence of steps would be most effective?
A.1) Create a histogram of 'Global_Sales'. 2) Create a bar chart of 'Genre' counts.
B.1) Filter the dataframe to only include 'Action' games. 2) Calculate the mean of 'Global_Sales' for this filtered data. 3) Compare this mean to the mean of 'Global_Sales' for the entire dataset.
C.1) Create a scatter plot of 'Genre' vs 'Global_Sales'. 2) Calculate the median of 'Global_Sales'.
D.1) Run `df.describe()` on the entire dataset. 2) Conclude that 'Action' games sell the most.
Challenging
You hypothesize that cars with more cylinders (a numerical feature) have lower fuel efficiency ('MPG', numerical). What is the most logical first step to investigate this?
A.Create a scatter plot with 'Cylinders' on one axis and 'MPG' on the other to look for a negative correlation
B.Calculate the mean 'MPG' for all cars in the dataset
C.Create a bar chart showing the count of cars for each cylinder number
D.Use `value_counts()` on the 'MPG' column to find the most common fuel efficiency
Challenging
A dataset on employees has two features. 'Years_at_Company' has a mean of 5.1 and a median of 5. 'Annual_Bonus' has a mean of $12,000 and a median of $5,000. What can you infer by comparing the distributions of these two features?
A.Both distributions are perfectly symmetrical
B.The 'Years_at_Company' distribution is likely symmetrical, while the 'Annual_Bonus' distribution is skewed by a few very high bonuses
C.The 'Annual_Bonus' distribution is symmetrical, while the 'Years_at_Company' distribution is skewed by a few employees who have been there for a very long time
D.There must be an error in the data, as the mean and median cannot be that different
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