Statistics For Dummies Direct

| Pitfall | Explanation | |---------|-------------| | Correlation ≠ causation | Ice cream sales and drowning are correlated (summer heat causes both). | | Small sample sizes | Extreme results likely by chance. | | Cherry-picking data | Choosing only favorable results. | | Ignoring multiple comparisons | 20 tests → one significant by chance at $\alpha=0.05$. | | Overinterpreting p-values | p=0.049 vs p=0.051 — nearly identical evidence, yet one “significant.” | | Assuming normal without checking | Use Q-Q plots or Shapiro–Wilk test. |

You will never calculate a t-test by hand in real life. Learn the concepts : p-value, confidence interval, random sample, bias. Statistics For Dummies

In nature and society, many things follow a "Normal Distribution." Imagine a bell-shaped curve: Most people are in the middle (the tall part of the bell). Fewer people are at the extreme ends (the "tails"). | | Ignoring multiple comparisons | 20 tests