Project : (time series analysis)Decoding Tesla: A Comprehensive Analysis of Open, High, Low, and Close Prices

Rawling Mukhen
10 min readFeb 4, 2024

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Introduction:

Welcome to my comprehensive analysis of Tesla’s stock price movements, where we delve deep into the intricate dynamics of Open, High, Low, and Close prices over time. In this project, we explore the fascinating world of financial time series data to decode the underlying patterns, trends, and correlations that drive Tesla’s stock performance.

Throughout this analysis, I meticulously examine the relationships between these key price indicators and uncover valuable insights that can inform investment strategies, portfolio management decisions, and risk mitigation techniques.

Key Highlights:

Exploring the Four Pillars:

I start by dissecting the Open, High, Low, and Close prices, the foundational pillars of stock market data. Through visualizations and statistical analysis, gain a nuanced understanding of how these prices interact and influence each other.

Open prices Over Time.

The plot illustrates the fluctuation in Tesla’s stock ‘Open’ prices over time, spanning from January 2015 to January 2024. The line chart vividly depicts the volatility and trend of the opening prices, showcasing periods of both growth and decline in the company’s stock value. Investors and analysts can use this visualization to track the historical performance of Tesla’s stock at the beginning of trading sessions, aiding in market analysis and investment decision-making processes.

High Prices Over Time.

This graph depicts the variation in Tesla’s stock ‘High’ prices over the period from January 2015 to January 2024. The line chart showcases the fluctuation in the highest recorded prices of Tesla’s stock over time, providing insights into the company’s stock performance during different market conditions. Investors and analysts can utilize this visualization to discern trends and patterns in Tesla’s stock highs, aiding in forecasting and decision-making processes related to investment strategies.

Low Prices Over Time

The line graph illustrates the fluctuations in Tesla’s stock ‘Low’ prices from January 2015 to January 2024. By observing the trajectory of low prices over time, investors and analysts can discern patterns and trends that may influence investment decisions. Understanding the dynamics of low prices provides valuable insights into the stock’s performance during different market conditions, aiding in risk assessment and strategic portfolio management strategies.

Close Prices Over Time

The line plot showcases the progression of Tesla’s ‘Close’ prices over the duration spanning from January 2015 to January 2024. Monitoring the trends and fluctuations in close prices is pivotal for investors and analysts to assess the overall performance and sentiment surrounding Tesla stock. The visualization aids in identifying key turning points, evaluating market sentiment, and making informed investment decisions based on the observed patterns and trends in close prices over time.

Unveiling Market Dynamics:

  • Moving Averages (MA): It includes two moving averages:
  • 50-day MA (orange line): This line represents the average closing price of the stock over the past 50 trading days. It helps smooth out short-term fluctuations and reveals the underlying trend in the stock price.
  • 200-day MA (red line): This line represents the average closing price of the stock over the past 200 trading days. It provides insights into the long-term trend of the stock price and helps investors identify significant shifts in the market sentiment.
  • Title and Labels: The graph is titled “Stock Price with Moving Averages”. The x-axis represents the date, while the y-axis represents the price of the stock.

Legend and Grid: The legend helps differentiate between the stock price line and the moving average lines. The gridlines assist in interpreting the data accurately.

Pinpointing Short-term Fluctuations:

Techniques like autocorrelation analysis, ARIMA (AutoRegressive Integrated Moving Average) modeling, or exponential smoothing can help analysts pinpoint short-term fluctuations in Tesla’s stock prices. By examining patterns in the data over shorter time frames, investors can identify temporary shifts in stock price behavior caused by factors like market sentiment, news events, or industry developments.

The plots shows the Autocorrelation Function (ACF) and Partial Autocorrelation Function (PACF) of the daily returns of Tesla’s stock price. These functions are essential in understanding the correlation and partial correlation between the current observation and its lagged values. By analyzing the ACF and PACF plots, we can identify potential patterns and dependencies in the time series data, which are crucial for building accurate forecasting models and understanding the underlying dynamics of the stock price movement over time.

Seasonality Analysis:

Original Time Series (Top Plot): This represents the raw data or the observed values over time. It includes all the fluctuations, trends, seasonality, and noise present in the data. The original time series provides the starting point for analysis.

Trend Component (Second Plot): The trend component captures the long-term movement or directionality of the time series data. It represents the overall pattern of growth or decline, ignoring short-term fluctuations and seasonal variations. The trend helps analysts identify underlying patterns and assess the overall direction of the series.

Seasonal Component (Third Plot): The seasonal component captures the periodic fluctuations or patterns that occur at regular intervals within the time series data. These patterns may repeat over fixed time periods, such as daily, weekly, monthly, or yearly cycles. Seasonal variations often reflect recurring events, such as holidays, seasons, or business cycles.

Residual Component (Bottom Plot): The residual component, also known as the remainder or error term, represents the variability in the original time series data that cannot be explained by the trend or seasonal components. It includes random fluctuations, irregular patterns, and noise that remain after removing the trend and seasonal effects. Analyzing the residual component helps identify unexpected or anomalous behavior in the data.

By applying these techniques and methods, analysts can gain a deeper understanding of the underlying dynamics driving Tesla’s stock price movements, enabling them to make more informed investment decisions and capitalize on opportunities in the market.

Detecting Anomalies:

Statistical methods like Z-score analysis or machine learning algorithms such as isolation forests or autoencoders can help detect anomalies or outliers in Tesla’s stock price data. Anomalies may indicate unusual or unexpected events that deviate from normal market behavior, such as sudden price spikes, crashes, or abnormal trading volumes. Detecting and analyzing these anomalies can provide valuable insights into potential market disruptions or emerging trends.

Identifying Unusual Events:

  • Anomalies represent unusual events or patterns in the data that deviate significantly from normal behavior. By detecting anomalies in Tesla’s stock price data, we can uncover potential market irregularities, unexpected price movements, or abnormal trading activities that may warrant further investigation.
  • Risk Management: Anomalies in stock price data can signal potential risks or vulnerabilities in the market. Identifying and understanding these anomalies can help investors and financial institutions manage risk more effectively by taking proactive measures to mitigate the impact of unexpected events on their portfolios.
  • Market Insights: Anomaly detection provides valuable insights into market dynamics and underlying trends that may not be apparent through traditional analysis methods. By analyzing anomalies in Tesla’s stock price data, we can gain a deeper understanding of market behavior, investor sentiment, and the factors driving price movements.
  • Decision Support: Anomaly detection algorithms serve as decision support tools for investors, traders, and financial analysts. By flagging anomalies in real-time or historical stock price data, these algorithms help stakeholders make more informed decisions about trading strategies, portfolio allocations, and risk management practices.

Now, let’s explore three different approaches for anomaly detection in Tesla’s stock price data: Z-score analysis, isolation forests, and autoencoders. Each approach offers unique advantages and can be tailored to specific characteristics of the data and the desired level of accuracy in anomaly detection.

Z-score

The daily return statistics provide insights into the distribution of Tesla’s stock price movements. With a mean return of 0.043 and a standard deviation of 0.311, the data highlights the volatility and potential for gains or losses in Tesla’s stock on a daily basis. The range from -0.560 to 1.766 signifies the spectrum of daily fluctuations, offering valuable context for investors and analysts
This histogram illustrates the distribution of Z-scores calculated from the daily returns of Tesla stock prices. Z-scores are used to identify anomalies in the data, with higher values indicating greater deviations from the mean daily return.
Histogram depicting the distribution of Z-scores for daily returns of Tesla stock prices. Anomalies are identified based on Z-score thresholds, highlighted in red, indicating significant deviations from the expected daily return behavior.
In the context of the DataFrame provided, the “True” values under the “Anomaly” column signify that the corresponding rows represent anomalies detected in the Tesla stock data. Anomalies, in this case, refer to data points that deviate significantly from the expected or normal behavior of the stock prices based on the Z-score analysis. These anomalies could indicate events or circumstances that are unusual or unexpected within the dataset, potentially warranting further investigation or analysis.

To mitigate anomalies detected using Z-score analysis in Tesla stock data, the company can consider the following strategies:

Improved Data Quality Control: Implement rigorous data quality control measures to ensure accurate and consistent data collection and processing. By maintaining high standards for data integrity and cleanliness, the likelihood of anomalies arising from data errors or inconsistencies can be minimized.

Advanced Monitoring Systems: Develop sophisticated monitoring systems that continuously track stock price movements and detect potential anomalies in real-time. Utilizing automated alerts and anomaly detection algorithms can help identify abnormal patterns or fluctuations promptly, enabling proactive intervention and response.

Enhanced Risk Management Practices: Implement robust risk management practices that incorporate anomaly detection techniques as part of the overall risk assessment framework. By systematically monitoring and analyzing deviations from expected stock price behaviors, the company can identify potential risks and take proactive measures to mitigate their impact on financial performance.

Advantages of Z-score Analysis:

Quantitative Assessment: Z-score analysis provides a quantitative method for evaluating data points relative to their mean and standard deviation. This allows for objective assessment and comparison of observations, facilitating data-driven decision-making.

Standardized Metric: The Z-score standardizes data by expressing observations in terms of standard deviations from the mean. This standardization enables meaningful comparisons across different datasets and variables, regardless of their scales or units of measurement.

Identification of Outliers: Z-score analysis helps identify outliers or anomalies within a dataset by flagging observations that fall outside a specified threshold of standard deviations from the mean. This enables analysts to pinpoint potentially unusual or noteworthy data points that merit further investigation.

Statistical Robustness: Z-score analysis is based on robust statistical principles, making it a reliable and widely used method for detecting anomalies and assessing the relative significance of data points within a distribution.

By leveraging Z-score analysis and implementing proactive measures to address detected anomalies, companies like Tesla can enhance their data-driven decision-making processes and minimize the impact of unexpected fluctuations in stock prices.

Isolation Forests

Isolation Forest is a machine learning algorithm widely used for anomaly detection tasks, particularly in high-dimensional datasets like time series data, where it efficiently identifies outliers by isolating them through random splits in the data structure.

The plot represents the daily returns of a financial asset (, Tesla stock) over time, with anomalies detected using the Isolation Forest algorithm highlighted in red. The Isolation Forest, implemented through the sklearn.ensemble module, is a machine learning algorithm designed for anomaly detection tasks. It constructs isolation trees to separate normal data points from anomalies, making it particularly effective for detecting outliers in high-dimensional datasets like time series data. By leveraging the Isolation Forest algorithm, we can efficiently identify unusual patterns or behaviors in the daily returns of the financial asset, which may signify significant market events or irregular trading activities.
The DataFrame with Anomalies Detected presents instances where anomalies were identified using the Isolation Forest algorithm. An anomaly is marked by a value of -1 in the ‘Anomaly’ column, indicating data points that diverge significantly from the norm. These anomalies may signify irregular patterns or outliers within the Tesla stock price and daily returns dataset.

The anomalies are identified based on Z-score calculations, where values with Z-scores beyond a certain threshold are flagged as anomalies. In contrast, the machine learning approach using Isolation Forest leverages an ensemble method that isolates anomalies by building a forest of decision trees. Unlike Z-score, which relies on statistical measures, Isolation Forest is capable of capturing complex patterns and outliers in high-dimensional datasets, making it more robust and versatile for anomaly detection tasks.

autoencoders

Autoencoders are a type of neural network architecture that is commonly used for unsupervised learning tasks, such as dimensionality reduction, data denoising, and anomaly detection. The basic idea behind autoencoders is to learn a compact representation of the input data by training the network to reconstruct its own inputs. They consist of an encoder and a decoder, where the encoder compresses the input data into a latent space representation and the decoder attempts to reconstruct the original input from this representation. but since we are not doing that we will not be taling much about it.

Here’s a breakdown of how autoencoders were used in the provided code and what the plots represent:

Data Preparation:

  • The input data consists of daily returns of a financial instrument.
  • Daily returns are calculated from the closing prices.
  • The data is preprocessed, including removing any missing values (NaNs) and standardizing the data using StandardScaler.

Autoencoder Architecture:

The autoencoder architecture consists of an input layer, an encoding layer, and a decoding layer.

  • The input dimension is determined by the shape of the scaled training data.
  • The encoding layer compresses the input data into a lower-dimensional representation. In this case, it uses the Rectified Linear Unit (ReLU) activation function.
  • The decoding layer attempts to reconstruct the original input from the encoded representation using a linear activation function.

Training the Autoencoder:

  • The autoencoder is trained using the mean squared error (MSE) loss function and the Adam optimizer.
  • The training data is the scaled input data, and the target data is also the scaled input data.
  • The validation data used during training is the scaled test data.

Anomaly Detection:

  • After training, the autoencoder is used to reconstruct the test set.
  • The mean squared error (MSE) between the original and reconstructed data points is calculated.
  • Anomalies are identified based on a threshold defined as the mean MSE plus twice the standard deviation of the MSE.

Visualization:

  • The plot displays the original scaled daily returns.
  • Anomalies detected by the autoencoder are highlighted in red.
  • This visualization helps to identify points where the model struggled to reconstruct the original data, indicating potential anomalies.

Regarding the advantage of autoencoders when working with very large datasets:

  • Autoencoders can be advantageous for large datasets because they can automatically learn useful representations of the data without requiring explicit feature engineering.
  • They have the ability to capture complex patterns and relationships in the data, making them suitable for tasks like anomaly detection, even in high-dimensional spaces.
  • With the rise of deep learning frameworks and the availability of parallel computing resources, autoencoders can be trained efficiently on large-scale datasets.
  • However, it’s important to note that training deep autoencoder models on large datasets can still be computationally intensive and may require substantial computational resources.

Conclusion:

In wrapping up our analysis of Tesla’s stock price movements, we’ve delved into the intricate dynamics of Open, High, Low, and Close prices over time. Through meticulous examination and data-driven insights, we’ve uncovered valuable patterns, trends, and correlations that drive Tesla’s stock performance.

Our journey began with a comprehensive exploration of the foundational pillars of stock market data: Open, High, Low, and Close prices. Through visualizations and statistical analysis, we gained a nuanced understanding of how these prices interact and influence each other, providing actionable insights for investors and analysts alike.

Moving beyond surface-level trends, I explored market dynamics using techniques like Moving Averages, Autocorrelation Analysis, and Seasonality Analysis. These methods not only revealed underlying market trends but also equipped us with the tools to identify short-term fluctuations and potential forecasting opportunities.

Anomaly detection emerged as a crucial aspect of our analysis, where we leveraged statistical methods and machine learning algorithms to identify unusual market behaviors and potential risks. By pinpointing anomalies, we provided valuable insights into market irregularities and offered strategies for risk management and decision-making.

My analysis underscores the power of data-driven insights in decoding the complexities of financial markets. By combining analytical rigor with a deep understanding of market dynamics, we’ve laid the groundwork for informed investment strategies, portfolio management decisions, and risk mitigation techniques.

As I conclude our exploration of Tesla’s stock price movements, i recognize the ongoing evolution of financial markets and the importance of staying attuned to emerging trends and patterns. Armed with our analytical toolkit and a commitment to continuous learning, i remain well-positioned to navigate the ever-changing landscape of financial data and drive informed decision-making in the years ahead.

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Rawling Mukhen
Rawling Mukhen

Written by Rawling Mukhen

Data scientist, Sharing insights from my research in data and IT.

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