For a certain online store, the distribution of number per hour is approximately normal with mean 1200 purchases and standard de
viation 200 purchases. for what proportion of hours will the number of purchases at the online store exceed 1400?
a)5%
b)68%
c)16%
d)32%
a)5%
b)68%
c)16%
d)32%
1 answer:
Answer: 16%
Step-by-step explanation:
When we have a normal distribution, the 100% of our sample will be placed in a "gaussian bell".
Where the middle of this bell coincides with the mean.
The mean, in this case, is 1200, and the standard deviation is 200.
In the image below you can see that between the points.
Mean + standard deviation and the end of the graph, we have:
13.5% + 2.35% + 0.15% = 16%
And particularly, if we want to know the percentage that exceed 1400, will be the same percentage above the mean plus the standard deviation.
mean = 1200
SD = 200
mean + standard deviation = 1200 + 200 = 1400.
Then the percentage that exceeds 1400 is equal to the percentage that we found above, then the correct option is C: 16%
You might be interested in
Answer:
COV (all stocks) = 0.55
COV (stocks and bonds) = 0.82
Step-by-step explanation:
Coefficient of Variation is used to measure variability.
It is defined as the ration of standard deviation and the mean.
It can be used to compare variability of two population or two samples.
Formula:
where are data points,
is the mean and n is the number of observations.
x: 14, 0, 39, 25, 32, 27, 28, 14, 14, 15
y = 6, 2, 29, 17, 26, 17, 17, 2, 3, 5
Since coefficient of variation of x is less compared to y, thus it could be said bonds does not reduce overall risk of an investment portfolio.