2 * 4/3= 8/3
3/4 * 2/1= 6/4= 3/2
3/2*8/3= 24/6= 4
So first we have to find out what the bottom number is so
8x+14
subsitute 8 for x
8(8)+14
64+14
78
so 156/78
an easy way to do this is to factor it out and find the 'ones' like 4/8=1/2 times 4/4 (4/4=1 and can be canceled out)
*=times
156=2*2*3*13
78=2*3*13
so (2*2*3*13)/(2*3*13)
2/1 times (2*3*13)/(2*3*13)
we can cross out the (2*3*13) and get
2 as the answer
Mean, m = 18 in
Standard deviation, SD = 2.2 in
Range: 16 ≤ X ≤ 21 in
Calculating Z value,
Z = (X-m)/SD
Then,
Z1 = (16-18)/2.2 ≈ -0.91
Z2 = (21-18)/2.2 ≈ 1.36
From Z table, and at Z1 = -0.91, and Z2 = 1.36;
P(16) = 0.1814
P(21) = 0.9131
Therefore,
P(16≤X≤21) = 0.9131 - 0.1814 = 0.7317
The probability that a child selected randomly measures between 16 and 21 in is 0.7317.
