Answer:
A sample of 179 is needed.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
That is z with a pvalue of 
, so Z = 1.44.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
A previous study found that for an average family the variance is 1.69 gallon?
This means that 
If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?
A sample of n is needed, and n is found for M = 0.14. So
Rounding up
A sample of 179 is needed.
Hello!
To find the greatest common factor, you must find all the factors of both numbers and see which similar one is the greatest.
27: (1,27) (3,9)
36: (1,36) (2,18) (3,12) (4,9) (6,6)
As you can see the, the greatest common factor is 9.
I hope this helps!
7+5= 12 ones. Or one ten and 2 ones. They made 12.
Answer:
Triangle ABC is similar but not congruent to Triangle XYZ
Step-by-step explanation:
When you dilate the size changes but the angles are the same with makes them similar and since the size of the triangles are different they cannot be congruent.
Answer:
600 L of 30% proof and 400 L of 80% proof is needed
Step-by-step explanation:
Let the amount of 30% smell proof be x while that of 80% smell proof is y
Then;
x + y = 1000 •••••(i)
Also;
30% of x + 80% of y = 50% of 1000
0.3x + 0.8y = 500 •••••(ii)
From i, x = 1000 - y
Put this into ii
0.3(1000-y) + 0.8y = 500
300 - 0.3y + 0.8y = 500
0.5y = 500-300
0.5y = 200
y = 200/0.5
y = 400 L
But x = 1000 - y
x = 1000 - 400 = 600 L
