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.
Answer:
X <= 4
Step-by-step explanation:
-3x - 24<= -36
Make -3x the subject, by carrying -24 to the other side
Note: Moving -24 to the other side changes to + 24
-3x <= -36 + 24
-3x <= - 12
Minus cancels minus
3x <= 12
Divide both sides by 3,to get the value of x
3x/3 <= 12/3
x <= 12/3
x <= 4
Therefore, x equals to 4
Answer:
20 minutes( 0.3333 hours) after they leave the station will they be 50 km apart, if the Two trains on opposite tracks leave the same station at the same time.
Step-by-step explanation:
One train travels at an average speed of 80 km/hr and the other travels at an average speed of 70 km/hr.
Answer:
m=-3
Step-by-step explanation:
m2-9=0
2 divied by 9 =3
when you have a positive number and a negitive number =a negitive
I think you get the point
