IB Stats

IB Stats

1. Uncertainty

   • Digital
     • +/- 1 of the smallest units
   • Analogue +/- 0.5 smallest unit
     • double the uncertainty when using a ruler

2. Mean

   • Average
     • Sum/ Sample size

3. Range

   • Largest-Smallest
     • used in error bars to see overlap

4. Data forms

   • Qualitative
     • Non specific:
   • Quantitative
     • Measurable data

5. Bias

   • How reliable is the data

6. Variance

   • The average of the squared differences from the mean

7. t-test

   • differences in mean / square root of sum of average standard deviations squared
   • If higher than tabulated value of 95% confidence, there is a significant difference
   • Degrees of freedom= total sample size - number of averages used
   • Dispute the null hypothesis to prove an alternative hupothesis

8. Standard Deviation

   • The square root of the variance
     • Forms bell curve
     • 1SDv 68% reliable
       • 2SDv 95% reliable
         • 3SDv 99% reliable