Answer: b is the answer
Step-by-step explanation:
To solve this problem, we use the formula:
z = (x – u) / s
where z is the z score value which can be obtained from
the tables, x is the sample value, u is the mean = 6.3 min, and s is the std
dev = 2.2 min
at P value = 0.90, the z = 1.28, finding for x:
x = z s + u
x = 1.28 * 2.2 + 6.3
x = 9.116
at P value = 1.0, the z = 3.49, finding for x:
x = z s + u
x = 3.49 * 2.2 + 6.3
x = 13.978 ~ 14
Therefore the longest 10% calls last about 9.1 minutes to
14 minutes
Answer:
Set A's standard deviation is larger than Set B's
Step-by-step explanation:
Standard deviation is a measure of variation. One way to judge the value of standard deviation is by looking at the range of the data. In general, a dataset with a smaller range will have a smaller standard deviation.
The range of data Set A is 25-1 = 24.
The range of data Set B is 18-8 = 10.
Set A's range is larger, so we expect its standard deviation to be larger.
__
The standard deviation is the root of the mean of the squares of the differences from the mean. In Set A, the differences are ±12, ±11, ±10. In Set B, the differences are ±5, ±3, ±1. We don't actually need to compute the RMS difference to see that it is larger for Set A.
Set A's standard deviation is larger than Set B's.
2/ 3 - (3 - 1) * 3 - 1 = -4
Simplify
= 2/-4
which is
= -2/4
Then simplify again
= -1/2
