The average score of local students on a college entrance exam is 110 with standard deviation of 15. The distribution is roughly bell-shaped. What is the percentage of local student with score below 95? Use the empirical rule to find the following percentage. A. 34%
B. 16%
C. 15.5%
D. 13.5%

B

Step-by-step explanation:

Here, we want to use the empirical rule to find the percentage.

The first thing we will do here is to find the z-score

Mathematically;

z-score = (x -mean)/SD

from the question, x = 95, mean = 110

and SD = 15

So z-score will be ;

(95-110)/15 = -15/15 = -1

So the probability we want to calculate is;

P(z < -1)

In terms of the empirical rule, we want to find the proportion of the scores which is less than 1 standard deviation of the mean.

According to the empirical rule, the proportion which is less than 1 standard deviation below the mean is 15.866% and the closest answer to this is 16% which is option B

By definition, the empirical rule is basically used in finding the proportion of values in this case scores which are at a certain standard deviation value below or above the mean. Below the mean are represented as negatives while above the mean are represented as positives.

step-by-step explanation:

if you want to solve percent error follow these steps.

1. subtract the accepted value from the experimental value.

2. take the absolute value of step 1.

3. divide that answer by the accepted value.

4. multiply that answer by 100 and add the % symbol to express the answer as a percentage.

if you want to solve percent of change just do this.

1. work out the difference (increase) between the two numbers you are comparing.

2. divide the increase by the original number and multiply the answer by 100. if your answer is a negative number then this is a percentage decrease.

hope this : )