1- We've established that heights of 10-year-old boys vary according to a Normal distribution with = 138 cm and = 7 cm

• What proportion of this population is less than 150 cm tall?
• What proportion is less than 140 cm in height?
• What proportion is between 150 and 140 cm?

2- The Wechsler Adult Intelligence Scale scores are calibrated to vary according to a Normal distribution with = 100 and = 15. What Wechsler scores cover the middle 50% of the population? In other words, identify the 25^th percentile and 75^th percentile of the population?