Data Science Interview Challenge

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Data Science Interview Challenge

Data Science Interview Challenge

1. Python

Introduction Challenge 1: List Comprehension Challenge 2: String Manipulation Challenge 3: Dictionary Manipulation Challenge 4: Nested Loops Challenge 5: Classes Theoretical Questions

2. NumPy

Challenge 1: Array Creation Challenge 2: Array Manipulation Challenge 3: Statistical Insights Challenge 4: Handling Missing Values Challenge 5: Subarray Sorting Theoretical Questions

3. Pandas

Challenge 1: DataFrame Creation Challenge 2: Data Grouping Challenge 3: Indexing and MultiIndexing Challenge 4: Altering DataFrame Challenge 5: Iterating Over Data Theoretical Questions

4. Matplotlib

Challenge 1: Fundamentals of Plotting Challenge 2: Other Graph Types Challenge 3: Subplots Challenge 4: Customizing Plots Challenge 5: Adding Text to Plots Theoretical Questions

5. Seaborn

Challenge 1: Visualizing Distributions Challenge 2: Exploring Categorical Data Challenge 3: Relational Plots Challenge 4: Regression Plots Challenge 5: Matrix Plots Theoretical Questions

6. Statistics

Challenge 1: Probabilities and Distributions Challenge 2: Bayes' Theorem Challenge 3: Hypothesis Testing Challenge 4: Confidence Intervals Challenge 5: Correlation Theoretical Questions

7. Scikit-learn

Challenge 1: Data Scaling Challenge 2: Basic Model Creation Challenge 3: Pipelines Challenge 4: Cross-validation Challenge 5: Hyperparameter Tuning Theoretical Questions

Theoretical Questions

1. In hypothesis testing, what is the null hypothesis, and what is the alternative hypothesis?

2. If the p-value in a hypothesis test is `0.03`, and the significance level (alpha) is set at `0.05`, do you reject or fail to reject the null hypothesis?

3. Explain what a 95% confidence interval means in the context of estimating a population mean.

4. If two variables have a correlation coefficient of `-0.85`, what does this tell you about their relationship?

5. Causation implies that:

6. In a scatter plot with points forming a straight line sloping upward from left to right, what type of correlation is likely present?

7. What statistical test is commonly used to determine if a correlation coefficient is significantly different from zero?

8. If you want to assess whether a set of data follows a normal distribution, which statistical test or plot is most appropriate?

9. In which real-life situation can the Chi-squared test be used?

10. Which of the following best describes the Central Limit Theorem (CLT)?

11. Which statement best captures the essence of the Law of Large Numbers?

In hypothesis testing, what is the null hypothesis, and what is the alternative hypothesis?

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Null: The hypothesis we hope to support; Alternative: The opposite of the null hypothesis.

Null: The hypothesis we hope to reject; Alternative: The opposite of the null hypothesis.

Null: The hypothesis we hope to support; Alternative: A random guess.

If the p-value in a hypothesis test is 0.03, and the significance level (alpha) is set at 0.05, do you reject or fail to reject the null hypothesis?

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Reject the null hypothesis.

Fail to reject the null hypothesis.

Explain what a 95% confidence interval means in the context of estimating a population mean.

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The interval contains 95% of the data points in the sample.

The interval is guaranteed to contain the population mean.

We are 95% confident that the random chosen data falls within the interval.

There is a 95% chance that this interval would cover the real mean of the entire population.

If two variables have a correlation coefficient of -0.85, what does this tell you about their relationship?

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They have a strong positive relationship.

There is no relationship between them.

They have a strong negative relationship.

The correlation coefficient is invalid.

Causation implies that:

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Correlation exists between two variables.

One variable is the direct cause of changes in another variable.

Statistical significance has been established.

The p-value is less than 0.05.

In a scatter plot with points forming a straight line sloping upward from left to right, what type of correlation is likely present?

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Positive correlation

Negative correlation

No сorrelation

Unclear

What statistical test is commonly used to determine if a correlation coefficient is significantly different from zero?

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Chi-squared test

ANOVA

T-test

None of the above

If you want to assess whether a set of data follows a normal distribution, which statistical test or plot is most appropriate?

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T-test

Shapiro-Wilk test

Scatter plot

Chi-squared test

In which real-life situation can the Chi-squared test be used?

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Comparing the average income of two different cities.

Determining the effect of a new medication on blood pressure levels in a clinical trial.

Examining the correlation between the number of hours spent studying and exam scores in a class of students.

Analyzing the relationship between smoking status and the development of health problems in a group of individuals.

Which of the following best describes the Central Limit Theorem (CLT)?

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The mean of a large sample drawn from any distribution will always equal the mean of the population.

The sum of random variables, regardless of distribution, will always be normally distributed.

The distribution of the sample mean of independent variables approaches a normal distribution as the sample size increases, regardless of the shape of the population distribution.

A large sample from a population will always be normally distributed.

Which statement best captures the essence of the Law of Large Numbers?

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The average of the results obtained from a large number of experiments should be close to the expected value and will tend to become closer as more trials are performed.

As the sample size increases, the sample distribution becomes more skewed.

The larger the sample size, the closer the sample variance is to the population variance.

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Abschnitt 6. Kapitel 6

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