Standard deviation

• Why do we carry out experiments in biology?

  to look for a difference between two or more sets of data

  to look for the correlation or association between two or more variables
• What is the null hypothesis?

  The null hypothesis is a statement that assumes there is no significant relationship or difference between variables being studied.
• What happens if the test statistic is less than the critical value:

  the p value is greater than 5%

  This means that the probability that the difference/correlation is due to chance alone is greater than 5%

  This means that the difference is not significant and is due to chance alone

  Accepting the null hypothesis
• What happens if the test statistic is greater than the critical value?


  It means that there p value is less than 5%

  This means the probability that the difference/correlation is due to chance alone is less than 5%

  So the difference is significant and isn’t due to chance alone

  Rejecting the null hypothesis
• What is standard deviation?

  It’s how spread out the data is from the mean
• What does an overlap in the SD bars suggest?

  There’s no significant difference between the ____ in ______ and the ____ in ______

  we know this as the SD bars overlap

  the difference in the ____ is not significant and is likely due to chance alone
• What do the SD bars represent when there is no overlap?

  There’s a significant difference between the ____ of ______ in ___ than the ____ of ______ in ___

  we know this as the SD do not overlap

  the difference in the____ is likely and is not due to chance