It is generally believed that nearsightedness affects about 1212% of children in a certain region. A school district tests the vision of 160160 incoming kindergarten children. How many would be expected to be nearsighted? What is the standard deviation for the number of nearsighted children in this group?

Step-by-step explanation:

Total number of kindergarten children in that region that were tested is 160

It is generally believed that nearsightedness affects about 12% of children in a certain region. Therefore,

The expected number of kindergarten children expected to be nearsighted is

12/100 × 160 = 19

Probability of success, p = 0.12

Probability of failure, q = 1 - p = 1 - 0.12 = 0.88

Standard deviation = √npq = √(160 × 0.12 × 0.88) = 4.11

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.