if a test given to 100 people have a mean of 3.5 and a standard deviation is .5, what is the standard deviation of someone who scores 1.5>
To calculate the standard deviation of a single person who scored 1.5, you would need more information about the underlying distribution of scores. However, given the mean and standard deviation of the test scores for a population of 100 people, we can provide some general information.
In this case, we know that the mean of the test scores is 3.5 and the standard deviation is 0.5. This means that for the entire population of 100 people, the average score is 3.5 and the spread of scores around the mean is 0.5. However, we cannot determine the standard deviation of an individual's score solely based on this information because we don't know the distribution of scores within the population.
If you have access to the individual scores or additional information about the distribution (e.g., normal distribution), you can calculate the standard deviation for an individual's score.