Answer:
The standard error of the mean is 4.5.
Step-by-step explanation:
As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:

The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.
The mean of the sample is:

The standard deviation of the sample is calculated as:

Then, we can calculate the standard error of the mean as:

Well, we could try adding up odd numbers, and look to see when we reach 400. But I'm hoping to find an easier way.
First of all ... I'm not sure this will help, but let's stop and notice it anyway ...
An odd number of odd numbers (like 1, 3, 5) add up to an odd number, but
an even number of odd numbers (like 1,3,5,7) add up to an even number.
So if the sum is going to be exactly 400, then there will have to be an even
number of items in the set.
Now, let's put down an even number of odd numbers to work with,and see
what we can notice about them:
1, 3, 5, 7, 9, 11, 13, 15 .
Number of items in the set . . . 8
Sum of all the items in the set . . . 64
Hmmm. That's interesting. 64 happens to be the square of 8 .
Do you think that might be all there is to it ?
Let's check it out:
Even-numbered lists of odd numbers:
1, 3 Items = 2, Sum = 4
1, 3, 5, 7 Items = 4, Sum = 16
1, 3, 5, 7, 9, 11 Items = 6, Sum = 36
1, 3, 5, 7, 9, 11, 13, 15 . . Items = 8, Sum = 64 .
Amazing ! The sum is always the square of the number of items in the set !
For a sum of 400 ... which just happens to be the square of 20,
we just need the <em><u>first 20 consecutive odd numbers</u></em>.
I slogged through it on my calculator, and it's true.
I never knew this before. It seems to be something valuable
to keep in my tool-box (and cherish always).
Answer:
58
Step-by-step explanation:
The triangles are congruent so you can do 180-32-90, which is equal to the angle at c
Answer:
this is answer
Step-by-step explanation:
Right now I don't have time. If u have doubt, send me a message. And I'll explain later.
hope it helps ☺️
Answer:
88 centimeters is the diameter of the cilinder
Step-by-step explanation:
The pressure on both ends of the lift must be the same. Assuming the piston is cilindrical, its area will be A=π*r² where r is half the diameter
Since pressure P=F/A And P1=P2
F1=2000kg.g
A1=π*r²
F2=25kg.g
A2=π*0.05²
2000/(π*r²)=25/(π*0.05²)
and we solve for A1
r²=2000*0.05²/25

r=
20*0.05/5=0.44m or 44cm
This is the radius, meaning that the diameter will be twice this number