15+15+15=45 7+7+7=21 4+4+4=12 4+15×7=?
1 answer:
You might be interested in
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:
<u>0.765 meters</u> long were the sticks when laid end to end.
Step-by-step explanation:
Given:
Rob laid three sticks end to end. The lengths of the sticks were 45 millimeters, 32 centimeters, and 4 decimeters.
Now, to find the length in meters of the sticks when laid end to end.
The lengths of the sticks are:
1st stick - 45 millimeters.
2nd stick - 32 centimeters.
3rd stick - 4 decimeters.
So, we convert the units of sticks into meters by using conversion factor:
1st stick:
1 millimeter = 0.001 meter.
45 millimeters = 0.001 × 45
45 millimeters = 0.045 meter.
2nd stick:
1 centimeter = 0.01 meter.
32 centimeters = 0.01 × 32
32 centimeters = 0.32 meter.
3rd stick:
1 decimeter = 0.1 meter.
4 decimeters = 0.1 × 4
4 decimeters = 0.4 meter.
Now, adding all the three sticks length to get the the length in meters of the sticks when laid end to end:
Therefore, 0.765 meters long were the sticks when laid end to end.