Answer:
61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.
Step-by-step explanation:
Given : We want 95% confidence that the sample mean is within 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.
To find : How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters?
Solution :
At 95% confidence the z-value is z=1.96
The sample mean is within 3 minutes of the population mean i.e. margin of error is E=3 minutes
The population standard deviation is s=12 minutes
n is the number of sample
The formula of margin of error is given by,
Substitute the value in the formula,
Squaring both side,
Therefore, 61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.
Answer:
2 units
Step-by-step explanation:
the radius is always half the diameter
d = 2r
Answer:
It should be 1,628 
.
Step-by-step explanation:
We see two shapes in the figure and those shapes are a rectangle and a circle. Let's find the area of the circle first. 25m won't help us find the area of the circle so let's pretend that 25m isn't there for now. 40m seems to be the diameter of the circle and to find the area of the circle we need to multiply the radius squared by Pi or 3.14. Half of 40 is 20 so we can multiply 20 squared by Pi to give us 1,256.63706. Do not round this number yet. As you can see this circle isn't a full circle. It's a semicircle. We can divide 1,256.63706 by 2 to find the area of a semicircle. You should get 628.31853 and round that to the nearest tenth and we get 628.32. Now let's keep that number in mind and find the area of the rectangle. Using a calculator we can easily multiply 40 and 25 to find the area of the rectangle, which is 1,000. Add 1,000 and 628.32 and our final results should be 1,628.32. I don't see this number in your options but option B is closely related to this answer. I hope this helps and if this answer is wrong then please give me some feedback on what I did wrong! Thank you!
Answer:
Step-by-step explanation:
Let
L-----> the length of a rectangle
W---> the width of a rectangle
we know that
-----> equation A
-----> inequality B
The inequality B represent the equation that could be used to find the possible values of the width
The solution for the width of the rectangle is all real numbers greater than 20 units
