Lighter cars are more fuel-efficient than heavier cars. An environmentalist would like to estimate the true mean weight of all cars. To do so, she selects a random sample of 30 cars and determines the 90% confidence interval for the true mean weight to be 2.8 to 3.4 tons. Which of these statements is a correct interpretation of the confidence level? There is a probability of 0.90 that the confidence interval (2.8, 3.4) captures the true mean weight of all cars.
The environmentalist can be 90% confident that the true mean weight of all cars is between 2.8 and 3.4 tons.
If many random samples of size 30 are selected from the population of all cars, approximately 90% of the sample means will be between 2.8 and 3.4 tons.
If many random samples of size 30 are selected from the population of all cars, about 90% of the intervals would capture the true mean weight of all cars.

1. 22

2. 1

3. 7

4. 18

step-by-step explanation

e2020 got it right

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

~

step-by-step explanation:

given expression is .

now we need to simplify the given expression .

we know that square root is equivalent to the power 1/2. so that means we can take half of the exponents to get the square root of given expression.

expanding that will give a very very large number so let's keep answer in exponent form.

"exterior angles = 360 / number of sides.

60 = 360 / sides

sides = 360 / 60

sides = 6"