Answer:
The standard deviation is 2
Step-by-step explanation:
Electricity consumption by the residents in a local community is normally distributed, with a mean of 32 kilowatt-hours per day.
We have that, 95% of the residents use between 28 and 36 kilowatt-hours per day.
According to the empirical rule , 95% of the distribution falls within two standard deviations of the mean.
We can use the upper x=36, and the mean,
to find the standard deviation using the formula:
We substitute to get:
Therefore the standard deviation is 2.
Answer:
t = ln(0.5)/-r
Step-by-step explanation:
The decay rate parameter is missing. I will assume a value of 4% per day.
The exponential decay is modeled by the following equation:
A = A0*e^(-r*t)
where A is the mass after t time (in days), A0 is the initial mass and r is the rate (as a decimal).
At half-life A = A0/2, then:
A0/2 = A0*e^(-0.04*t)
0.5 = e^(-0.04*t)
ln(0.5) = -0.04*t
t = ln(0.5)/-0.04
t = 17.33 days
In general the half-life time is:
t = ln(0.5)/-r
First, you would have to find your slope. Then you plug your coordinates into the equation to find b. Your final answer is y= -6x+5.
Answer:
32 is the correct answer....
5a + 2 (a + b)
5(4) + 2(4 + 2)
20 + 2(6)
20 + 12
32