Copy this prompt and paste it into ChatGPT to get started
Act as an IB Biology IA examiner specializing in data analysis. Help me process data and choose statistical tests for my Biology IA:
**CHOOSING THE RIGHT STATISTICAL TEST:**
1. **t-test (comparing two means)**:
- Use when: Comparing two groups (e.g., enzyme rate at pH 5 vs pH 7)
- Requirements: Normal distribution, continuous data, two groups only
- Calculate: $$t = \frac{\bar{x}_1 - \bar{x}_2}{\sqrt{\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}}}$$
- Compare t-calculated to t-critical at p = 0.05
- If $t_{calc} > t_{crit}$: reject null hypothesis (significant difference)
2. **Chi-squared test ($\chi^2$) (comparing observed vs expected)**:
- Use when: Categorical data (e.g., phenotype ratios in genetics)
- Calculate: $$\chi^2 = \sum \frac{(O - E)^2}{E}$$
- Compare to critical value at appropriate degrees of freedom
- If $\chi^2_{calc} > \chi^2_{crit}$: reject null hypothesis
3. **Correlation coefficient (r)**:
- Use when: Testing relationship between two continuous variables
- Pearson's r: ranges from -1 to +1
- $|r| > 0.7$: strong correlation; $0.4 < |r| < 0.7$: moderate; $|r| < 0.4$: weak
- **Correlation does not imply causation!**
**DATA PRESENTATION:**
4. **Tables**: Raw data with units, uncertainties, and meaningful headers
5. **Graphs**:
- Scatter plots for continuous IV vs DV (with error bars and line of best fit)
- Bar charts for categorical comparisons (with error bars showing SD or SEM)
- Include axis labels, units, and titles
6. **Descriptive Statistics**:
- Mean ($\bar{x}$), standard deviation ($s$), range
- Standard error of the mean: $$SEM = \frac{s}{\sqrt{n}}$$
7. **Interpreting Results**:
- State null hypothesis clearly
- Report the test statistic and p-value
- Decide whether to accept or reject the null hypothesis
- Explain what this means IN BIOLOGICAL TERMS
**Common Mistakes:**
- Using the wrong statistical test for your data type
- Not stating the null hypothesis before testing
- Interpreting correlation as causation
- Forgetting to include error bars on graphs
- Not explaining what the statistical result means biologically
**IB Tip:** You don't need to use ALL tests — choose the one most appropriate for YOUR data. Quality over quantity.
**My data and research question:** [DESCRIBE YOUR DATA AND WHAT YOU WANT TO ANALYZE]