Question 1155440
The weights for newborn babies is approximately normally distributed with a mean of 6 pounds and a standard deviation of 1.4 pounds.
Consider a group of 1000 newborn babies:
1. How many would you expect to weigh between 4 and 9 pounds?
2. How many would you expect to weigh less than 7 pounds?
3. How many would you expect to weigh more than 6 pounds?
4. How many would you expect to weigh between 6 and 10 pounds?
solution 
1 mean=6 sd=1.4 total number 1000 find number weight between 4 to 9 pounds 
z=x-mue/sd
4-6/1.4=-2/1.4 =-1.42   z value by table  0.0793
z=9-6/1.4=3/1.4=2.14     z value by table 0.9904
effective value  0.9904-0.0793 =0.9111
number of children =1000x0.9111=911,1
911 children 
2. less than 7 pounds 
z=7-6/1.4=1/1.=0.71
number of children born less than  7 pounds =0.7611x1000=761.1
means 761 children less than 7 pounds 
3.more than 6 pounds 
z=6-6/1.4=0/1.4=0  z>0 z value as per table  0.5
number of children born 1000x0.5=500
number of children born more than 6 pounds are 500

z<0.71   z value by table 0.7611
4. weight  between 6 to 10 pounds 
z=6-6/1.4=0/1.4 =0  value of z by table 0.5
z=10-6/1.4=4/1.4 =2.85   value of z by table 0.9977
0<z<2.85  
 value will be 0.9977-0.5000=0.4977
number of children born between 6 to 10 pounds =0.4977x1000=497.7  means 498