Given that mean=3750 hours and standard deviation is 300:
Then:
<span>a. The probability that a lamp will last for more than 4,000 hours?
P(x>4000)=1-P(x<4000)
but
P(x<4000)=P(z<Z)
where:
z=(x-</span>μ)/σ
z=(4000-3750)/300
z=0.833333
thus
P(x<4000)=P(z<0.8333)=0.7967
thus
P(x>4000)=1-0.7967=0.2033
<span>b.What is the probability that a lamp will last less than 3,000 hours?
P(x<3000)=P(z<Z)
Z=(3000-3750)/300
z=-2.5
thus
P(x<3000)=P(z<-2.5)=0.0062
c. </span><span>.What lifetime should the manufacturer advertise for these lamps in order that only 4% of the lamps will burn out before the advertised lifetime?
the life time will be found as follows:
let the value be x
the value of z corresponding to 0.04 is z=-2.65
thus
using the formula for z-score:
-2.65=(x-3750)/300
solving for x we get:
-750=x-3750
x=-750+3750
x=3000</span>
Answer:
Starting time: 1:37
Step-by-step explanation:
Instead of proof to solve the problem, let us prove that the starting time above is correct;
1. There are 60 minutes in an hour, so 60 - 37 = the minutes 'till 2:00, or 23 minutes
2. Knowing that the time the truck stopped driving through the neighborhood was 5 minutes past 2:00, the minute difference being 23 + 5, or <em>28 minutes</em>
<em>Proved: 28 minutes</em>
Answer:
The answer to that question is b
Step-by-step explanation:
5 for the first one and 7 for the second hope this helps
Answer:
is the value of x. Step-by-step explanation: We have been given the two terms which are equivalent means they have equal value: and . So, by the given information: we have to solve for x: Firstly, we will cross multiply so, we will get: After simplification we will get the final result is the value of x.
Step-by-step explanation:
