ASSUME THE THE MEAN WEIGHT OF CHILDREN AGES 7 IS 50 POUNDS AND A STANDARD DEVIATION OF 10. wHAT IS THE PROBABLITY THAT A RANDOM SELECTED 7 YEAR OLD WILL HAVE A WEIGHT THAT IS LESS THAT 65

2 answers

You have to find the z-score.

65-50 = 15 then divide by 10 which is z = 1.5

You can then use a z-table or a stat calculator to find the probablity less than 65%

Depending on the table, you may want to find the probability of z = 1.5 or greater and then subtract that number from 1 to get the less than.
For a normal distribution, what is the probability of randomly selecting a z score greater than Z=- 2.0