The time is takes a police department to arrive at the scene of a crime is normally distributed with a mean of 4.5 minutes and a standard deviation of 0.8 minutes. What percent of time will the police take 4 minutes or less to arrive? Calculate the z-score, and use the table on page 447 of the textbook

Respuesta :

Given:

[tex]Mean\text{ }\mu\text{ =4.5, standard deviation }\sigma\text{ =0.8, and x =4.}[/tex]

Required:

We need to find the percentage of the time will the police take 4 minutes or less to arrive.

Explanation:

Consider the z-score formula.

[tex]z=\frac{x-\mu}{\sigma}[/tex]

[tex]Substitute\text{ }\mu\text{ =4.5, }\sigma\text{ =0.8, and x =4 in the formula.}[/tex][tex]z=\frac{4-4.5}{0.8}[/tex][tex]z=-0.625[/tex]

P-value from Z-Table

[tex]P(x<4)=0.26599[/tex]

Multiply by 100 to find the percentage.

[tex]P(x<4)\text{ \%}=0.26599\times100[/tex][tex]P(x<4)\text{ \%}=26.599\text{ \%}[/tex][tex]P(x<4)\text{ \%}=27\text{ \%}[/tex]

Final answer:

27 % of the time will the police take 4 minutes or less to arrive.