Answer:
554 executives should be surveyed.
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 Z-table as such z has a p-value of 
.
That is z with a pvalue of 
, so Z = 1.96.
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.
Standard deviation of 3 hours.
This means that 
The 95% level of confidence is to be used. How many executives should be surveyed?
n executives should be surveyed, and n is found with 
. So
Rounding up:
554 executives should be surveyed.
In case A, as the error would be a difference of 1, the assumption could be mantained, but in case B the difference will be bigger, showing that the ratio is not 3:1 but 4:1.
<h3><u>Ratios</u></h3>
Given that a preliminary study was carried out to test the hypothesis that the ratio of white to dark herons on the island was 3:1, but A) a small census found 16 white morphs and 4 dark, to determine if the assumption of a 3 :1 ratio could be rejected, and B) to determine the same question if the census were larger with 160 white morphs and 40 dark, the following calculations must be made:
A)
- 3 + 1 = 4
- 16 + 4 = 20
- 4 = 20
- 3 = X
- 60 / 4 = X
- 15 = X
- Therefore, as the error would be a difference of 1, the assumption could be mantained.
B)
- 3 + 1 = 4
- 160 + 40 = 200
- 150 = 3:1
- In this case, the difference will be bigger, showing that the ratio is not 3:1 but 4:1.
Learn more about ratios in brainly.com/question/1504221
Answer:
12 in
Step-by-step explanation:
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