To determine the average water use, 109 people must be sampled.
1.9 gallons is the standard deviation.
E = 0.15 gallons maximum error
1.9 gallons on average
90% is the critical value.
1.645 is the 90% confidence interval.
sample size requirement,
n = (((z ÷ 2) × σ) ÷ E)²
n = (((1.645 ÷ 2) × 1.9) ÷ 0.15)²
n = ((0.8225 × 1.9) ÷ 0.15)²
n = (1.5627 ÷ 0.15)²
n = (10.418)²
n = 108.53 ≈ 109
As a result, the minimal sample size necessary to determine the mean water use = 109.
It is determined by dividing the average standard error by the squared of the sample size, and it decreases with increasing sample size. In other words, when the sample size is sufficiently big, the population mean approaches the population mean.
To learn more about the sample interval at
brainly.com/question/13664567?referrer=searchResults
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Answer: The area of the top of the walkway is 1,050 square feet
Step-by-step explanation:
Hi, to answer this question we simply have to apply the next formula:
Area of a rectangle: width x length (of the base)
Replacing with the values given and solving for A:
A = 25 feet x 42 feet = 1,050 square feet
In conclusion, the area of the top of the walkway is 1,050 square feet
Feel free to ask for more if needed or if you did not understand something.
321.7. It's rounded down to the appropriate number of figures.
2000, you just need to put three zeros at the end of the number.
