Question

The summer monsoon rains bring 80% of India's rainfall and are essential for the country's agriculture. Records going back more than a century show that the amount of monsoon rainfall varies from year to year according to a distribution that is approximately Normal with mean 852 millimeters (mm) and standard deviation 82 mm. Use the 68-95-99.7 rule to answer the questions. (a) Between what values do the monsoon rains fall in the middle 95% of all years? between 606 and 1098 mm between 164 and 1540 mm between 688 and 1016 mm O between 770 and 934 mm (b) How small are the monsoon rains in the driest 2.5% of all years? less than 21.3 mm less than 770 mm less than 606 mm less than 688 mm Question Source Moore, The Basic Practice of Statistics, Be Publisher

Answer 1

(2) Using 68-95-99.7 role, 95% of all values fall between mean- 2 SD and mean +2SD. 852- 2*82 and 852 + 2x82 on 688 and 1016 m. less than 688 mm. (6) (C) 2-1.96 (using standard normal table).