Answer:
25%
Step-by-step explanation:
Given parameters:
Amount earned by Jessica per month = 800
Total savings target per year = 2400
Unknown:
Percentage of savings = ?
Solution:
The total earning per year will be the amount earned per month multiplied by the total number months;
Amount earned in a year = 12 x 800 = 9600
Let the percentage of savings per year = y%
Now;
2400 = x 9600
y = 25%
The empirical rule you're referring to is the 68-95-99.7 rule, which asserts that for a normal (bell-shaped) distribution, approximately 68% of the distribution lies within 1 standard deviation of the mean; 95% lies within 2 standard deviations of the mean; and 99.7% lies within 3 standard deviations of the mean.
Let be the random variable denoting vehicle speeds along this highway. We want to find
. To use the rule, we need to rephrase this probability in terms of the mean and standard deviation.
Notice that , and
. In other words, 61 and 79 both lie exactly 3 standard deviations away from the mean, so
.