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:
Step-by-step explanation:
The left hand side of the equation contains proper fractions while the right hand side of the equation contains mixed fraction. The mixed fraction can be changed to improper fraction. 1 2/3 becomes 5/3
To breakdown the left hand side of the equation, we would take lowest common factor of 5 and 15. It is 15
Considering 4/5, if 15 divides 5,the result is 3. Multiplying 3 by 4 gives 12. So it becomes
12/15
Considering 13/15, if 15 divides 15,the result is 1, Multiplying 1 by 13 gives 13. So it becomes
13/15
The equation becomes
(12 + 13)/15 = 5/3
25/15 = 5/3
Simplifying 25/15 to its lowest terms, it becomes 5/3 so
5/3 = 5/3
The sample proportion has an approximately normal distribution, with the mean being the population mean and the standard deviation (i.e. the standard error of the sampling proportion) equal to
SE = sqrt(p*q/n) where p is the population proportion q is 1-p, and n is the sample size.
<span>(Typically, for a confkdence interval, the sample proportion and its complement are substituted for p and q.) </span>
The margin of error will be Zc*SE, where Zc is the critical value of Z for the level of confidence required. The confidence interval, then, will be the sample proportion, plus or minus the margin of error.
For a 90% confidence interval, Zc is 1.645.
<span>So the margin of error is 1.645 * sqrt(.9*.1/400), roughly .025. So your confidence interval would be around [.875, .925]
The best and most correct answer among the choices provided by your question is the second choice or letter C which is 3%.
I hope my answer has come to your help. Thank you for posting your question here in Brainly.</span>
C= 15 + 2h
2h reprents the totals of hours times the 2 dollar hour use.
the 15 is added because its the deposit fee
