Answer: A. 20%
Step-by-step explanation:
First, to find the total number of teachers, we can add 25+32+18+5+20=100
Next, we divide the number of teachers in 2014 (20) by the total number of teachers (100) as follows:
20 ÷ 100 = 0.2
Finally, to make 0.2 a percentage, we can multiply 0.2 X 100 = 20
Therefore, the correct answer is A.
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:
bottom right.
Step-by-step explanation:
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Answer:
la verdad noce no me acuerdo
Answer:
Standard form for straight line y = m x + b where m is slope
m' = -m or m * m' = -1
answer a or y = - 8/7 + 4 satisfies this requirement
