CS 215 - Data Interpretation and Analysis

Instructor: Ajit Rajwade and Suyash Awate
Office: SIA-218, KReSIT Building
Email:

Lecture Venue: LC 001 (Lecture Hall Complex)
Lecture Timings: Slot 11, Tuesday and Friday 3:30 to 5:00 pm

Instructor Office Hours (at the Lecture Venue): Tuesday and Friday, 5:00 to 6:00 pm, i.e. immediately after class, or by appointment via email (also feel free to send queries over email or moodle)

Teaching Assistants: Dibyangshu Mukherjee, Yadnyesh Patil, Jay Bansal, Aman Kansal, Pranay Reddy Samala, Anurag Maurya, Deepak Singh Baghel, Ashish Aggarwal
Emails: (dbnshu, yadny, jaybansal, amankansal, pranayr, anuragcse, deepakbaghel, ashishaggarwal ) AT CSE DOT iitb DOT ac DOT in

Topics to be covered (tentative list)


Intended Audience

2nd year BTech students from CSE

Learning Materials and Textbooks

Computational Resources


Grading Policy (tenative)


Other Policies


Tutorials

Quizzes

Lecture Schedule:

Please check moodle for links to lecture videos. You will be able to download these videos via your xyz@iitb.ac.in accounts.

Date

Content of the Lecture

Assignments/Readings/Notes

Lecture Video 1 (parts 1 and 2)
  • Introduction, course overview and course policies
  • Slides: Course Overview (see moodle)
Lecture Video 2 Descriptive Statistics
  • Descriptive statistics: key terminology
  • Methods to represent data: frequency tables, bar/line graphs, frequency polygon, pie-chart
  • Concept of frequency and relative frequency
  • Cumulative frequency plots
  • Interesting examples of histograms of intensity values in an image
  • Data summarization: mean and median
  • "Proof" that median minimizes the sum of absolute deviations - using calculus
  • Slides: Descriptive statistics (see moodle)
  • Readings: section 2.1, 2.2 from the textbook by Sheldon Ross
Lecture Video 3
  • Properties of the mean and median
  • "Proof" that median minimizes the sum of absolute deviations - using calculus
  • Proof that median minimizes the sum of absolute deviations, without using calculus
  • Concept of quantile/percentile
  • Calculation of mean and median in different ways from histogram or cumulative plots
Lecture Video 4
  • Standard deviation and variance, some applications
  • Two-sided Chebyshev inequality with proof; One-side Chebyshev inequality (Chebyshev-Cantelli inequality)
  • Proof of one-sided Chebyshev's inequality
  • Slides: Descriptive statistics (see moodle)
  • Readings: section 2.1, 2.2, 2.3, 2.4, 2.6 from the textbook by Sheldon Ross
Lecture Video 5
  • Concept of correlation coefficient and formula for it; proof that its value lies from -1 to +1
  • Correlation coefficient: properties; uncentered correlation coefficient; limitations of correlation coefficient and Anscombe's quartet
  • Correlation and causation
  • Slides: Descriptive statistics (check moodle)
  • Readings: section 2.1, 2.2, 2.3, 2.4, 2.6 from the textbook by Sheldon Ross
  • The correlation versus causation debtate: Link 1, Link 2, Link 3.
Lecture Videos 6-8
  • MATLAB Demo Codes (check moodle): vector and matrix operations, very basic image input/output, basic statistical operations, plots of various types (scatterplot, plot, boxplot, surf, surfc)
Lecture Videos 9-11 Discrete Probability
  • Discrete probability: sample space, event, composition of events: union, intersection, complement, exclusive or, De Morgan's laws
  • Boole's and Bonferroni's inequalities
  • Conditional probability, Bayes rule, False Positive Paradox
  • Independent and mutually exclusive events
  • Birthday paradox
  • Slides: Discrete Probability (check moodle)
  • Readings: Chapter 3 from the textbook by Sheldon Ross
Lecture 12 Random variables
  • Random variable: concept, discrete and continuous random variables
  • Probability mass function (pmf), cumulative distribution function (cdf) and probability density function (pdf)
  • Expected value for discrete and continuous random variables
Lecture 13
  • Law of the Unconscious Statistician (LOTUS): Expected value of a function of a random variable
  • Linearity of expectation
  • The mean and the median as minimizers of squared and absolute losses respectively (with proofs for both)
  • Variance and standard deviation, with alternate expressions
  • Properties of variance
  • Markov's inequality and its proof
Lecture 14
  • Proof of Chebyshev's inequality (two-sided) using Markov's inequality
  • Weak law of large numbers and its proof using Chebyshev's inequality
  • Statement of strong law of large numbers
  • Concept of joint PMF, PDF, CDF
Lecture 15
  • Concept of conditonal CDF, PDF, with verification/understanding of stated formula
  • Concept of covariance, concept of mutual independence and pairwise independence
  • Properties of covariance
  • Covariance: properties, correlation versus independence
Lecture 16
  • Covariance: properties, correlation versus independence
  • Concept of moment generating function, two different proofs of uniqueness of moment generating function for discrete random variables, properties of moment generating functions
Lecture 17 Families of random variables
  • Concept of families of random variables
  • Bernoulli PMF: mean, median, mode, variance, MGF
  • Binomial PMF: relation to Bernoulli PMF, mean, median, mode, variance, plots, MGF, difference between binomial and geometric distribution
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.1 from the textbook by Sheldon Ross
Lecture 18
  • Multinomial PMF - generalization of the binomial, mean vector and covariance matrix for a multinomial random variable, MGF for multinomial
Lecture 19
  • Hypergeometric distribution: genesis, mean, variance
  • Applications of the hypergeometric distribution in counting of animals via the capture-recapture method
Lecture 20
  • Gaussian distribution: Derivation of mean, variance, MGF, median, mode
  • CDF of a Gaussian and its relations to error functions; probability of a Gaussian random variable to have values between mu +/- k sigma.
  • Gaussian (normal) PDF: motivation from the central limit theorem
  • Illustration of central limit theorem, statement of central limit theorem
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.1,5.2,5.5,6.1,6.2 from the textbook by Sheldon Ross
Lecture 21
  • Statement of central limit theorem and its extensions; proof of CLT using MGF
  • Relation between CLT and the law of large numbers
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.1,5.2,5.5,6.1,6.2 from the textbook by Sheldon Ross
Lecture 22
  • Illustration of central limit theorem: coss toss example
  • Gaussian tail bounds
  • Distribution of the sample mean and the sample variance, Bessel's correction;
  • Chi-squared distribution - definition, genesis, MGF
Lecture 23
  • Chi-squared distribution - definition, genesis, MGF, properties; use of a chi-square distribution toward defining the PDF of the sample variance
  • Uniform distribution: mean, variance, median, MGF; applications in sampling from a pre-specified PMF; application in generating a random permutation of a given set
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.1,5.2,5.5,6.1,6.2,6.3,6.4 from the textbook by Sheldon Ross
Lecture 24
  • Poisson distribution: mean, variance, MGF, mode, addition of Poisson random variables, examples; derivation of Poisson from binomial
  • Relation between Poisson and Gaussian distributions, examples
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.2,5.6 from the textbook by Sheldon Ross
Lecture 25
  • Exponential distribution: mean, median, MGF, variance, property of memorylessness, minimum of exponential random variables
  • Slides: Families of Random variables (check moodle)
  • Readings: Section 5.6 from the textbook by Sheldon Ross
Lecture 26 Parameter Estimation
  • Parameter Estimation
  • Concept of parameter estimation (or parametric PDF/PMF estimation)
  • Maximum likelihood estimation (MLE)
  • MLE for parameters of Bernoulli, Poisson, Gaussian and uniform distributions
  • Least squares line fitting as an MLE problem
  • Slides and derivations: Parameter Estimation (check moodle)
  • Readings: Section 5.6 from the textbook by Sheldon Ross
  • Readings: Sections 7.1, 7.2, 7.5, 7.7, 9.2 (for least squares line fitting) of the textbook by Sheldon Ross
Lecture 27
  • MLE for parameters of uniform distributions
  • Least squares line fitting as an MLE problem
  • Slides and derivations: Parameter Estimation (check moodle)
  • Readings: Section 5.6 from the textbook by Sheldon Ross
  • Readings: Sections 7.1, 7.2, 7.5, 7.7, 9.2 (for least squares line fitting) of the textbook by Sheldon Ross
Lecture 28
  • Concept of estimator bias, mean squared error, variance
  • Estimators for interval of uniform distribution: example of bias
  • Concept of two-sided confidence interval and one-sided confidence interval
  • Confidence interval for mean of a Gaussian with known standard deviation
  • Confidence interval for variance of a Gaussian
  • Slides and derivations: Parameter Estimation (check moodle)
  • Readings: Sections 7.1, 7.2, 7.5, 7.7, 9.2 (for least squares line fitting) of the textbook by Sheldon Ross
Lecture 29
  • Concept of two-sided confidence interval and one-sided confidence interval
  • Confidence interval for mean of a Gaussian with known standard deviation
  • Confidence interval for variance of a Gaussian
  • Slides and derivations: Parameter Estimation (check moodle)
  • Readings: Sections 7.1, 7.2, 7.5, 7.7, 9.2 (for least squares line fitting) of the textbook by Sheldon Ross
Lecture 30
  • Concept of nonparametric density estimation
  • Concept of histogram as a probability density estimator
  • Bias, variance and MSE for a histogram estimator for a smooth density (with bounded first derivatives) which is non-zero on a finite-sized interval; derivation of optimal number of bins (equivalently, optimal binwidth) and optimal MSE O(n^{-2/3})
  • Derivation of MSE, bias, variance for a histogram
  • (Read section 6.1 only. These notes are by Prof. Yen-Chi Chen from the Univ. of Washington, Seattle. A local copy of the pdf is here
  • Readings: Sections 7.1, 7.2, 7.5, 7.7, 9.2 (for least squares line fitting) of the textbook by Sheldon Ross