Answer:
i think is n = 4. Sorry if wrong.
Step-by-step explanation:
The confidence interval is
![15.8\pm0.905](https://tex.z-dn.net/?f=15.8%5Cpm0.905)
We first find the z-score for this confidence interval:
Convert 90% to a decimal: 90/100 = 0.9
Subtract from 1: 1-0.9 = 0.1
Divide by 2: 0.1/2 = 0.05
Subtract from 1: 1-0.05 = 0.95
Using a z-table (http://www.z-table.com) we see that the z-score for this value is directly between 1.64 and 1.65, so we will use 1.645.
The confidence interval is given by:
Add and subtract as normal however just make sure you are always moving the decimal point in the right place.
Answer:
C.
is greater than zero.
Step-by-step explanation:
We know that graph is obtained from the function of the form
. According to the graph and if
, we find that:
(1)
(2)
By (1) and (2):
![-k < 0](https://tex.z-dn.net/?f=-k%20%3C%200)
![k > 0](https://tex.z-dn.net/?f=k%20%3E%200)
Hence, correct answer is C.
%change=100(final-initial)/initial
%change=100(63-90)/90
%change= -30%
So the price was decreased by 30%