A set of average city temperatures in december are normally distributed with a mean of 16.3° C and a standard deviation of 2°C. What proportion of temperatures are between 12.9°C and 14.9°C?

We have been given that a set of average city temperatures in december are normally distributed with a mean of 16.3° C and a standard deviation of 2°C. We are asked to find the proportion of temperatures that are between 12.9°C and 14.9°C.

First of all, we will find the z-score corresponding to 12.9°C and 14.9°C using z-score formula.

Similarly, we will find z-score corresponding to 14.9°C.

Now we need to find probability of z-score between .

Using normal distribution table, we will get:

Therefore, of temperatures are between 12.9°C and 14.9°C.

step-by-step explanation: it is d

the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

the root or roots of a polynomial are the values of the variable that makes the polynomial equal to 0. we can find the roots of a polynomial making the expression equal to 0 and then, isolating the variable (it it has just one variable).

for example, given the following polynomial:

the root or zero of the polynomial, can be found by making the expression equal to 0, and then, isolating the variable, so, finding the root we have:

therefore, we have that the root of the polynomial is equal to 2.

we must remember that the number of roots that a polynomial can have, will depend on the degree of the polynomial, a first degree polynomial have will have one single root, a second degree polynomial (quadratic expression) may have two roots and so.

hence the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

have a nice day!