Final answer:
Joseph scored 164 points.
Step-by-step explanation:
The z-score is a measure of how many standard deviations above or below the mean a particular data point falls. In this case, Joseph's z-score is -1, which means he scored 1 standard deviation below the mean. Since the average score on the stats midterm is 170 points with a standard deviation of 6 points, we can calculate Joseph's score using the formula:
Score = (Z-Score * Standard Deviation) + Mean
Plugging in the values, we get:
Score = (-1 * 6) + 170 = 164 points