Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
2. Describing Data with Tables and Graphs
Visualizing Qualitative vs. Quantitative Data
Problem 2.4.6
Textbook Question
Airport Data Speeds Listed below are the cellular data speeds (Mbps) from Sprint and Verizon measured at nine different airports (based on data from CNN). What would the presence of a correlation suggest about Sprint and Verizon?


1
Step 1: Understand the concept of correlation. Correlation measures the strength and direction of a linear relationship between two variables. A positive correlation indicates that as one variable increases, the other tends to increase, while a negative correlation indicates that as one variable increases, the other tends to decrease.
Step 2: Organize the data provided. The table lists cellular data speeds (Mbps) for Sprint and Verizon at nine different airports. Treat Sprint's data as one variable (X) and Verizon's data as another variable (Y).
Step 3: Calculate the correlation coefficient (r). Use the formula for ÃÛÌÒapp's correlation coefficient: r = (Σ((X_i - XÌ„)(Y_i - Ȳ))) / (√(Σ(X_i - XÌ„)^2) * √(Σ(Y_i - Ȳ)^2)). Here, XÌ„ and Ȳ are the means of Sprint and Verizon data speeds, respectively.
Step 4: Interpret the correlation coefficient. If r is close to +1, it suggests a strong positive correlation; if r is close to -1, it suggests a strong negative correlation; if r is close to 0, it suggests no correlation. This will help determine if Sprint and Verizon data speeds are related.
Step 5: Discuss the implications of correlation. If a correlation exists, it suggests that Sprint and Verizon data speeds may be influenced by similar factors at airports, such as network infrastructure or environmental conditions. However, correlation does not imply causation, so further investigation would be needed to determine the cause of the relationship.

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