Hi guys! could you please help me out with this real quick? Thanks y'all! -Grace :))
1 answer:
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A)
well, we know the elevator's rate is -20 f/s, ok, so every second, is dropping 20 feet, therefore, "y" is "distance from the ground floor", so when y = 0, meaning the distance to the ground floor is 0, so you ARE at the ground floor then.
and "x" is how many seconds you've been in the elevator.
now, she got in the elevator for 6 seconds, so, the elevator went down by 20 * 6, or 120 feet down, reason why the slope is negative, when she stopped, she was 350 feet away from the ground floor still though.
if the elevator went down 120 feet, and she's still 350 feet from the ground floor, that means she boarded the elevator at 120 + 350 feet, or 470 feet.
b)
well, we know the elevator's rate is -20 f/s, ok, so every second, is dropping 20 feet, therefore, "y" is "distance from the ground floor", so when y = 0, meaning the distance to the ground floor is 0, so you ARE at the ground floor then.
and "x" is how many seconds you've been in the elevator.
now, she got in the elevator for 6 seconds, so, the elevator went down by 20 * 6, or 120 feet down, reason why the slope is negative, when she stopped, she was 350 feet away from the ground floor still though.
if the elevator went down 120 feet, and she's still 350 feet from the ground floor, that means she boarded the elevator at 120 + 350 feet, or 470 feet.
b)
Answer:
A sample of 997 is needed.
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 z-score that has a p-value of .
The margin of error is of:
A previous study indicates that the proportion of left-handed golfers is 8%.
This means that
98% confidence level
So , z is the value of Z that has a p-value of
, so
.
How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 2%?
This is n for which M = 0.02. So
Rounding up:
A sample of 997 is needed.