Answer:
Step-by-step explanation:
Original price of the music box = $80
Price after 20% discount = Original price - discount
= 80 - 20% of 80
= 80 -
= 80 - 16
= $64
Price after 40% discount = 80 - 40% of $80
= 80 - 32
= $48
Original price of A faux Ming vase = $60
Price after 20% discount = Original price - discount
= 60 - 20% of $60
= 60 - 12
= $48
Price after 40% discount = Original price - discount
= 60 - 40% of 60
= 60 - 24
= $36
Answer:
a)
b) n = 381
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
90% confidence level
So , z is the value of Z that has a pvalue of
, so
.
a. Assume that nothing is known about the percentage of computers with new operating systems. n = ?
When we do not know the proportion, we use , which is when we are going to need the largest sample size.
The sample size is n when M = 0.01.
b. Assume that a recent survey suggests that 99% of computers use a new operating system. n = ?
Now we have that . So
Rouding up
n = 381