Answer:
31.43 oz
Step-by-step explanation:
12.40 + 8.03 + 11 = 31.43
The question is incomplete! Complete question along with answer and step by step explanation is provided below.
Question:
The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours.
If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?
Given Information:
standard deviation = σ = 30 hours
confidence level = 99%
Margin of error = 6 hours
Required Information:
sample size = n = ?
Answer:
sample size = n ≈ 165
Step-by-step explanation:
We know that margin of error is given by
Margin of error = z*(σ/√n)
Where z is the corresponding confidence level score, σ is the standard deviation and n is the sample size
√n = z*σ/Margin of error
squaring both sides
n = (z*σ/Margin of error)²
For 99% confidence level the z-score is 2.576
n = (2.576*30/6)²
n = 164.73
since number of bulbs cannot be in fraction so rounding off yields
n ≈ 165
Therefore, a sample size of 165 bulbs is needed to ensure a margin of error not greater than 6 hours.
Answer: 12.56 / 4 = 3.1416 =9.4248
Step-by-step explanation: pi by the 2 squared gives u the area of all the circle but u need to fin 3/4 of the circle so divide by 4 and the result of the dividion x 3 gives u the answer
Answer:
-15 ft or 15 ft below sea level
Step-by-step explanation:
He started at +8 ft.
Then he went 23 ft down, that is -23 ft.
8 ft + (-23 ft) = 8 ft - 23 ft = -15 ft
Answer: -15 ft
Answer:
a)20 is the answers for the question
Step-by-step explanation:
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