Final answer:
A hypothesis test is important because it provides a way to draw conclusions about the population based on sample data, even if the raw data already shows a difference or trend. It helps determine if the observed difference or trend is statistically significant.
Step-by-step explanation:
A hypothesis test is important even if the raw data already shows a difference between two groups or an increase or decrease over time, because it provides a way to draw conclusions about the population based on sample data. A hypothesis test helps determine if the observed difference or trend in the data is statistically significant, meaning it is unlikely to have occurred by chance. This helps researchers make informed decisions and draw valid conclusions.