Answer:
-3-(-7)=4 ,-7-(-3)=-4
Step-by-step explanation:
+ × += +
- × - = +
Step-by-step explanation:
The mean is 27 and the standard deviation is 4.
23 is 1 standard deviation below the mean, and 31 is 1 standard deviation above the mean. According to the empirical rule, 68% of the population is between -1 and +1 standard deviations.
68% of 1200 is 816.
19 is 2 standard deviations below the mean, and 35 is 2 standard deviations above the mean. According to the empirical rule, 95% of the population is between -2 and +2 standard deviations.
95% of 1200 is 1140.
