Answer:
The value of b is -5
Step-by-step explanation:
To work out the mean of a data set add all the numbers together and divide them by the number of data items there are.
18 + 14 + 8 + 22 + 25 + 8 = 95
95/6 = 15.8 (that answer is rounded)
The point-slope formula is y-y1=m(x-x1). You will then substitute into this equation. The answer will be y-2=-8(x+3).
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:
D
Step-by-step explanation:
If you look at the right side of each piecewise function, you will see the x-values. That is what we will be focusing on in this explanation. All four equations have x <u>></u> 4, and we know that to be true. If you look at the equation on the graph going South West, you will see that the endpoint is at x=1. Only 1 equation, D, has this in the piecewise function. To confirm it is D, you can see that 1<x<4 is also in the piecewise function, and all the values line up with their corresponding y-values.
Hope this helps! :)
