In statistics, the 68–95–99.7 rule, also known as the three-sigma rule or empirical rule, states that nearly all values lie within three standard deviations of the mean in a normal distribution.
About 68.27% of the values lie within one standard deviation of the mean. Similarly, about 95.45% of the values lie within two standard deviations of the mean. Nearly all (99.73%) of the values lie within three standard deviations of the mean.
In mathematical notation, these facts can be expressed as follows, where x is an observation from a normally distributed random variable, μ is the mean of the distribution, and σ is its standard deviation:
P( μ – σ ≤ x ≤ μ + σ ) ≈ 0.6827
P( μ –2σ ≤ x ≤ μ + 2σ ) ≈ 0.9545
P( μ –3σ ≤ x ≤ μ + 3σ ) ≈ 0.9973
So here A = μ – σ = 78.7 – 3.5 = 75.2 (answer
Answer:
y=-2x-4
Step-by-step explanation:
y=mx+b
count the slope (-2/1)
find the y-intercept(0,-4)
write it out (-2/-1)x-4
simplify (-2x-4)
Answer:
C(n) = 12 + 1.5(n – 1)
Step-by-step explanation:
A certain four-cylinder combination lock has 50 numbers on it.
It is a four cylinder combination lock
Each cylinder has 50 numbers
So we have to choose 4 numbers for 4 cylinders
_____ , ______ , ______, _____
you turn to a number on the first cylinder
We have 50 numbers so we have 50 combinations
__50___ , ______ , ______, _____
Repetitions are allowed so we do the same for remaining three
50 , 50 , 50 , 50
50 * 50 * 50* 50 = 6250000
There are 6250000 different lock combinations .
