Assessment statement
1.1.1 State that error bars are a graphical representation of the variability of data.
1.1.2 Calculate the mean and standard deviation of a set of values.
1.1.3 State that the term standard deviation is used to summarize the spread of values around the mean, and that 68% of the values fall within one standard deviation of the mean.
1.1.4 Explain how the standard deviation is useful for comparing the means and the spread of data between two or more samples.
1.1.5 Deduce the significance of the difference between two sets of data using calculated values for t and the appropriate tables.
1.1.6 Explain that the existence of a correlation does not establish that there is a causal relationship between two variables.

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