-530
I hope this helps! (^_^)
Answer:
(i) The student who weighed the rock 20 times.
Step-by-step explanation:
The margin of error of a confidence interval is:

In which z is related to the confidence level,
is the standard deviation of the population and n is the size of the sample.
From the equation above, the larger the size of the sample, the lower the margin is, that is, the narrower the interval is.
In this question:
A student weighed the rock 20 times and other the 5. From above, the one who weighed the rock 20 times will have the more precise interval.
So the correct answer is:
(i) The student who weighed the rock 20 times.
Answer:
-8
Step-by-step explanation:
Both the numbers are negative so you add them together and keep the negative sign
Answer:
50 km
Step-by-step explanation:
So the map has a scale of 1 cm: 20 km. Next, you look at how far they are apart and see if the scale and the distance on the map are the same measurement. In this case, they are both centimeters so they stay the same. Then, all you do is multiple the real size, 20 km, by
2.5
1
. Then, 20 x 2.5=50. So the answer is 50 km
Answer:
40
Step-by-step explanation: