In a mid-size company, the distribution of the number of phone calls answered each day by each of the 12 receptionists is bell-shaped and has a mean of 37 and a standard deviation of 6. Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 25 and 49?

Respuesta :

Answer:

0.9544 or 95.44%

Step-by-step explanation:

Given: Mean= 37

          Standard deviation= 6

          x= 25 and 49.

Now, solving to find the percentage of daily phone calls numbering between 25 and 49.

[tex]Lets\ x_1= 25\ and\ x_2= 49[/tex]

first calculating the z-score for daily 25 phone calls.

Formula; [tex]z-score= \frac{x-mean}{standard\ deviation}[/tex]

z-score= [tex]\frac{25-37}{6}[/tex]

z-score= [tex]\frac{-12}{6} = -2[/tex]

z-score for daily 25 phone call is -2.

Next, calculating the z-score for daily 49 phone calls.

z-score= [tex]\frac{49-37}{6}[/tex]

z-score= [tex]\frac{12}{6} = 2[/tex]

z-score for daily 49 phone call is 2.

We can observe that there is change in z-score for 25 phone call and 49 phone call.

Lets use the normal distribution table to find the percentage of daily phone calls numbering between 25 and 49.

⇒ Percentage of daily phone calls numbering between 25 and 49= [tex](z-score\ x_2)- (z-score\ x_1)[/tex]

⇒ Percentage of daily phone calls numbering between 25 and 49= [tex](z-score\ 2)- (z-score\ -2)[/tex]

Using normal distribution table

⇒ Percentage of daily phone calls numbering between 25 and 49= [tex]0.9772 - 0.0228= 0.9544[/tex]

Hence, 0.9544 or 95.44% is the percentage of daily phone calls numbering between 25 and 49.

"0.9544 or 95.44% is the percentage of daily phone calls numbering between 25 and 49 To understand more information check below".

Calculation of Standard Deviation

Given: Mean= 37

Standard deviation is = 6

Then, x is = 25 and 49.

Now, We are solving to find the percentage of daily phone calls numbering between 25 and 49.

Then, Lets x₁ = 25 and x₂ = 49

Now First we calculate the z-score for daily 25 phone calls.

Then we using a Formula; z - score = x - mean/ standard deviation

Then, z-score is = 25 - 37/6

z-score is = -12/6 = -2

∴ z-score for daily 25 phone calls is -2.

Now, calculate the z-score for daily 49 phone calls.

After that, z-score is = 49 - 37/6

Then, z-score is = 12/6 = 2

∴ z-score for daily 49 phone calls is 2.

Now, We can observe that there is a change in the z-score for 25 phone calls and 49 phone calls.

Let's use the normal distribution table to find the percentage of daily phone calls numbering between 25 and 49.

After that, ⇒ the Percentage of daily phone calls numbering between 25 and 49=

(z - scores x₂) - (z - score x₁)

Then, ⇒ the Percentage of daily phone calls numbering between 25 and 49=

(z - scores x₂) - (z - score - 2)

Using a normal distribution table

After that, ⇒ Percentage of daily phone calls numbering between 25 and 49=

Then, 0.9772 - 0.0228 is = 0.9544

Therefore, 0.9544 or 95.44% is the percentage of daily phone calls numbering between 25 and 49.

Find more information about Standard Deviation here:

https://brainly.com/question/22920224