Divide 83.524 by pi then take half of that answer .
the answer should be 13.29 or 13.3
Answer:
Go look on M a t h w a y
Step-by-step explanation:
M A t h w a y
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:
102336
Step-by-step explanation:
Im bored
Answer:
x = (64 + 5) ÷ 3
Step-by-step explanation:
3x - 5 = 64
Add 5 to both sides: 3x = 64 + 5 = 69
Divide both sides by 3: x = 69 ÷ 3 = 23
So the answer is x = (64 + 5) ÷ 3
Note: If we didn't add the parentheses then using the order of operation x = 64 + 5 ÷ 3 would be x = 64 + 
= 65 
