Maths

• Standard deviation shows the mean spread of data
• Standard deviation squared

  =(x-mean)squared/number of values -1
• When standard deviation bars overlap it’s a clue that the difference is not statistically significant and is likely to be due to chance.
• When standard deviation error bars do not overlap it’s a clue that the difference may be significan so it is unlikely to be due to chance.
• If the probability of difference in a result being greater than 0.05 there is no significant difference
• If the probability of difference in result occurring is less than 0.05 there is a significant difference.
• If the probability of difference in a result occurring due to chance is equal to 0.05 then the difference is significant.
• P Value= Probability of difference in a result occurring due to chance
• Rate of reaction= amount of reactant used/time taken to use it