Answer:
Step-by-step explanation:
given that certain tubes manufactured by a company have a mean lifetime of 800 hours and a standard deviation of 60 hours.
Sample size n =16
Std error of sample mean = 
x bar follows N(800, 15)
the probability that a random sample of 16 tubes taken from the group will have a mean lifetime
(a) between 790 and 810 hours,
=
(b) less than 785 hours
, (c) more than 820 hours,
(d) between 770 and 830 hours
=
Answer:
position: (-6, -4)
range: 6
Step-by-step explanation:
The equation is that of a circle centered at (-6, -4) with a radius of √36 = 6. We presume that the "position" is that of the circle's center, and the "range" is the radius of the circle.
___
The standard form equation of a circle with center (h, k) and radius r is ...
(x -h)^2 +(y -k)^2 = r^2
Matching parts of the equation, we find ...
h = -6, k = -4, r = √36 = 6.
Answer:
(-4,9)
Step-by-step explanation:
To solve the system of equations, you want to be able to cancel out one of the variables. In this case, it'd be easiest to cancel out the x variables. To do this, you'll want to multiply everything in the first equation by 2 (2(x-5y=-49)=2x-10y=-98). Then, you can add the two equations together. 2x and -2x will cancel out, so you'll be left with -11y=-99. Next, solve for x by dividing both sides of the equation by -11, which will give you y=9. This is your y-coordinate! At this point, you're halfway to the answer as you just need your x-coordinate. It's not too difficult to find the x-coordinate, since you just substitute 9 into one of the equations. It doesn't matter which one you choose as you should get the same answer with both. I usually substitute the y-value into both equations, though, just to make sure I'm correct. Once you put the y-value into the equations, you should get x=-4 after solving it. :)
4, 7 and 9 are mutually coprime, so you can use the Chinese remainder theorem.
Start with
Taken mod 4, the last two terms vanish and we're left with
We have 
, so we can multiply the first term by 3 to guarantee that we end up with 1 mod 4.
Taken mod 7, the first and last terms vanish and we're left with
which is what we want, so no adjustments needed here.
Taken mod 9, the first two terms vanish and we're left with
so we don't need to make any adjustments here, and we end up with 
.
By the Chinese remainder theorem, we find that any 
such that
is a solution to this system, i.e. 
for any integer 
, the smallest and positive of which is 149.
Answer:
a) 0.125
b) 0.015635
c) 0.00000095367431640625
Step-by-step explanation:
a) 
b) 
c) 
