The salary of teachers in a particular school district is normally distributed with a mean of $50,000 and a standard deviation of $2,500. Due to budget limitations, it has been decided that the teachers who are in the top 2.5% of the salaries would not get a raise. What is the salary level that divides the teachers into one group that gets a raise and one that doesn't?

A. -1.96
B. 1.96
C. 45,100
D. 54,900

Respuesta :

Answer:

D. 54,900

Step-by-step explanation:

We have been given that the salary of teachers in a particular school district is normally distributed with a mean of $50,000 and a standard deviation of $2,500.

To solve our given problem, we need to find the sample score using z-score formula and normal distribution table.

First of all, we will find z-score corresponding to probability [tex]0.975(1-0.025)[/tex] using normal distribution table.  

From normal distribution table, we get z-score corresponding is [tex]1.96[/tex].

Now, we will use z-score formula to find sample score as:

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

[tex]z[/tex] = Z-score,

[tex]z[/tex] = Sample score,

[tex]\mu[/tex] = Mean,

[tex]\sigma[/tex] = Standard deviation

[tex]1.96=\frac{x-50,000}{2,500}[/tex]

[tex]1.96*2,500=\frac{x-50,000}{2,500}*2,500[/tex]

[tex]4900=x-50,000[/tex]

[tex]4900+50,000=x-50,000+50,000[/tex]

[tex]54900=x[/tex]

Therefore, the salary of $54900 divides the teachers into one group that gets a raise and one that doesn't.

Q&A Education