The manager of a computer help desk operation has collected enough data to conclude that the distribution of time per call is normally distributed with a mean equal to 8.21 minutes and a standard deviation of 2.14 minutes. The manager has decided to have a signal system attached to the phone so that after a certain period of time, a sound will occur on her employees' phone if she exceeds the time limit. The manager wants to set the time limit at a level such that it will sound on only 8 percent of all calls. The time limit should be:

The time limit should be 11.26 minutes.

Step-by-step explanation:

We are given that the distribution of time per call is normally distributed with a mean equal to 8.21 minutes and a standard deviation of 2.14 minutes i.e.;

Mean, = 8.21 minutes      and     Standard deviation, = 2.14 minutes

Also, z score = ~ N(0,1)

It is also given that a sound will occur on her employees' phone if she exceeds the time limit.

Let X = time limit after which sound which occur

The manager wants to set the time limit at a level such that it will sound on only 8 percent of all calls i.e.; P(X > x) = 0.08

    P(X > x) = 0.08   ⇒ P( > ) = 0.08

             ⇒ P(Z > ) = 0.08

In the z table, the critical value which exceeds the area of 0.08 is 1.427 which means;

            ⇒   = 1.427

            ⇒ x = (1.427 * 2.14) + 8.21

            ⇒ x = 11.264 minutes

Therefore, the time limit at a level such that it will sound on only 8 percent of all calls is 11.26 minutes .

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.