[Step-by-Step] SAT verbal scores are normally distributed with a mean of 450 and a standard deviation of 120. a) Use the Empirical Rule to find intervals centered


Question: SAT verbal scores are normally distributed with a mean of 450 and a standard deviation of 120.


a) Use the Empirical Rule to find intervals centered at the mean of 450 that will include 68%, 95%, and 99.7% of all scores.

(b) Use the Empirical Rule to find what percent of scores lie between 210 and 570

(b) By symmetry, we have that 47.5% of the cases fall in (210, 450). Also, 34% fall in (450, 570). Therefore, 81.5% of the cases lie between 210 and 570.

Use the following to answer questions #13, 14, 15:


A local fire station receives an average of 0.50 rescue calls per day. Using software, Table 3 (Poisson probabilities), or the Poisson probability formula, find the following
probabilities for a randomly selected day:

  1. Fewer than 2 calls will be received

  2. Between and including one or four calls will be received.

(More specifically, we use Poisson (1, 0.5, true) in Excel).

(b)We need to compute now

\[\Pr (1\le X\le 4)=\Pr (X\le 4)-\Pr (X<1)=\Pr (X\le 4)-\Pr (X=0)=0.048598\]

Use the following to answer #16, 17, and 18:


The distribution of salaries of elementary school teachers is approximately normal with mean m = $32000 and a standard deviation s = $5000.

a) If an individual teacher is selected at random, what is the probability that his or her salary is less than $36000?

(b) What is the cutoff salary for teachers who have salaries in the top 10%?

(c) If 35 teachers are randomly selected, what is the probability that their mean salary is between $31500 and $36000? Use the Central Limit Theorem.

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