← Statistics for Data Science learning pathStatistics for Data Science · Module 5 of 10
Sampling and confidence intervals
Estimate population values with uncertainty.
📖 Key ideas
- A point estimate is a single best guess (e.g., sample mean).
- Standard error = SD / √n; it shrinks as n grows.
- A 95% confidence interval gives a range likely to contain the true value.
- Bigger samples give narrower intervals.
- Report estimates with their uncertainty.
💡 Real-life example: A confidence interval is a fishing net: a wider net is more likely to catch the true fish.
Point estimateSingle best guess
Standard errorVariability of a sample statistic
Confidence intervalRange likely containing the true value
Margin of errorHalf-width of the interval