Answer:
4π
Step-by-step explanation:
We are asked to calculate the area of a circle whose diameter is equal to 4, we know that the area of the circle is given by the following equation:
A = π * (r ^ 2)
where r is the radius of the circle, we know that the radius of the circle is half the diameter, therefore:
r = d / 2 = 4/2
r = 2
replacing, we are left with:
A = π * (2 ^ 2)
A = 4π
Which means that the area of the circle is 4π
THat would be A , B, C and E
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:
5,2
Step-by-step explanation: