1. The problem: Understand what standardisation means and how to apply it in problems. 2. Standardisation is a process used in statistics to transform data so it has a mean of 0 and a standard deviation of 1. 3. The formula for standardisation (also called z-score) is: $$z = \frac{x - \mu}{\sigma}$$ where $x$ is the original value, $\mu$ is the mean of the data, and $\sigma$ is the standard deviation. 4. This formula converts any value $x$ into a standard score $z$ that tells you how many standard deviations $x$ is from the mean. 5. To apply standardisation in problems: - Calculate the mean $\mu$ and standard deviation $\sigma$ of your data set. - Use the formula to find the $z$-score for each value. - The $z$-score helps compare values from different distributions or identify outliers. 6. In future questions, when asked to standardise or find a z-score, always use the formula above. 7. Remember, standardisation is useful for comparing data points on the same scale and is a key step in many statistical analyses.