Answer:
try D it seems right to me
Answer:
100
Step-by-step explanation:
if SP>CP,
It is profit [SP - CP = Profit]
if CP>SP,
It is loss [CP - SP = Loss]
Here in the question CP>SP so,
loss = CP - SP
=200 - 100
= 100
9514 1404 393
Answer:
(-2, 1)
Step-by-step explanation:
Rotating a point 180° about the origin in either direction is equivalent to reflecting it across the origin. The effect is to negate both coordinates.
(x, y) ⇒ (-x, -y) . . . . . rotation 180°
(2, -1) ⇒ (-2, 1) . . . . . P' rotated 180° from P
The coordinates of the rotated point are (-2, 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.
