Simple! 1/3 times 3 equals 3/3, or 1.
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:
Step-by-step explanation:
The absolute change in game length is ...
(180 min) -(150 min) = 30 min . . . . change in game length
__
The relative change is expressed as a fraction of the original game length:
(30 min)/(150 min) × 100% = 20% . . . . relative change in game length
Answer:
Good, Good, Good, Good, GOOOOOOOOOOOOOOOOOOOO000D. It's E btw I think I don't know
Step-by-step explanation:
Answer: x= 21.6
Step-by-step explanation:
12^2 + 18^2 =x^2
144 + 324 =x^2
468 = x^2
c= 21.633
To the nearest tenth place is c= 21.6
