Answer:
2.87%
Step-by-step explanation:
We have the following information:
mean (m) = 200
standard deviation (sd) = 50
sample size = n = 40
the probability that their mean is above 21.5 is determined as follows:
P (x> 21.5) = P [(x - m) / (sd / n ^ (1/2))> (21.5 - 200) / (50/40 ^ (1/2))]
P (x> 21.5) = P (z> -22.57)
this value is very strange, therefore I suggest that it is not 21.5 but 215, therefore it would be:
P (x> 215) = P [(x - m) / (sd / n ^ (1/2))> (215 - 200) / (50/40 ^ (1/2))]
P (x> 215) = P (z> 1.897)
P (x> 215) = 1 - P (z <1.897)
We look for this value in the attached table of z and we have to:
P (x> 215) = 1 - 0.9713 (attached table)
P (x> 215) =.0287
Therefore the probability is approximately 2.87%
So theres 4 hours and 60min equals 1 hour, so multiply 4 by 60 to get 240, so theres 240 minutes of time on the mp3. So 1/6 of that total time (240min) was on jazz, so what you do is divide 240 by 6 to get 40, so every 1/6 is 40min. So you could say he spend 40min listening to jazz, or you could say he spent 2/3 of an hour listening to jazz
Answer: $70 per year.
Step-by-step explanation:
Let's say that x is the number of years that has passed and y is how much the stamp is worth.
So we know that in zero years the stamp was worth $420 because that is the time Sheri gave her brother Sam the stamp. That could bring up the coordinates (0,420) .
Now we know that in 8 years it was worth $980 and that could be the coordinates (8,980)
To find the rate of change we need to find the different between the y value and divide it by the difference in the x values.
420 - 980 = -560
0-8 = -8
-560/-8 = 70
The rate of change is 70 which means that it grew by $70 every year.
X - an amount
To increase an amount by 3% you can multiply the amount by 1.03.
