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Complete Question
The life of a semiconductor laser at a constant power is normally distributed with a mean of 7,000 hours and a standard deviation of 600 hours. If three lasers are used in a product and they are assumed to fail independently, the probability that all three are still operating after 7,000 hours is closest to? Assuming percentile = 95%
Answer:
0.125
Step-by-step explanation:
Assuming for 95%
z score for 95th percentile = 1.645
We find the Probability using z table.
P(z = 1.645) = P( x ≤ 7000)
= P(x<Z) = 0.95
After 7000 hours = P > 7000
= 1 - P(x < 7000)
= 1 - 0.95
= 0.05
If three lasers are used in a product and they are assumed to fail independently, the probability that all three are still operating after 7,000 hours is calculated as:
(P > 7000)³
(0.05)³ = 0.125
Answer:


Step-by-step explanation:

Option #2
11.56 is rounded to 12 because the 6 rounds the 5 to a 6. 11.6 then rounds to 12.
Answer:
At least 547 records need to be studied.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence interval
, we have the following confidence interval of proportions.

In which
Z is the zscore that has a pvalue of
.
And the margin of error is:

95% confidence interval
So
, z is the value of Z that has a pvalue of
, so
.
In this problem, we have that:






At least 547 records need to be studied.
the solutions to the related equation are 0,2,3 .
<u>Step-by-step explanation:</u>
Here we have , function f(x) = x3 – 5x2 + 6x . Graph of this function is given below . We need to find What are the solutions to the related equation . Let's find out:
Solution of graph means the value of x at which the value of f(x) or function is zero . We can determine this by seeing the graph as at what value of x does the graph intersect or cut x-axis !
At x = 0 .
From the graph , at x=0 we have f(x) = 0 i.e.
⇒ 
⇒ 
⇒ 
At x = 2 .
From the graph , at x=2 we have f(x) = 0 i.e.
⇒ 
⇒ 
⇒ 
At x=3 .
From the graph , at x=3 we have f(x) = 0 i.e.
⇒ 
⇒ 
⇒ 
Therefore , the solutions to the related equation are 0,2,3 .