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.
first calculating the z-score for daily 25 phone calls.
Formula;
z-score=
z-score=
∴ z-score for daily 25 phone call is -2.
Next, calculating the z-score for daily 49 phone calls.
z-score=
z-score=
∴ 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=
⇒ Percentage of daily phone calls numbering between 25 and 49=
Using normal distribution table
⇒ Percentage of daily phone calls numbering between 25 and 49=
Hence, 0.9544 or 95.44% is the percentage of daily phone calls numbering between 25 and 49.