Answer:
a). The mean = 1000
The variance = 999,000
The standard deviation = 999.4999
b). 1000 times , loss
Step-by-step explanation:
The mean of geometric distribution is given as , 
And the variance is given by, 
Given : 
= 0.001
The formulae of mean and variance are :



a). Mean = 
=
= 1000
Variance = 
= 
= 999,000
The standard deviation is determined by the root of the variance.

=
= 999.4999
b). We expect to have play lottery 1000 times to win, because the mean in part (a) is 1000.
When we win the profit is 500 - 1 = 499
When we lose, the profit is -1
Expected value of the mean μ is the summation of a product of each of the possibility x with the probability P(x).

= $ 0.50
Since the answer is negative, we are expected to make a loss.
Since you're looking for the unit rate, you can start do this:

And yes,

is also correct, it's just switching around the 15
Answer:
1.) 90 ways
2.) 15,600 ways
3.) 24 ways
Step-by-step explanation:
1.) Let's say we are given 2 digits not equal to each other...The number of different orderings would be 2*1 = 2, or if we wanted the number of ways to order 2 digits chosen : 10*9 = 90 ways
2.) The number of ways to arrange 3 letters from 26 letters is:
26 Permutes 3 = 26! / (26 -3)! = 26*25*24 = 15,600 ways to choose 3 letters in a certain order
3.) 4 different chores. The number of ways to do them = 4*3*2 *1 = 24 ways
First, note that

is always positive (except for x=0), so

must be always negative.
Thus, the only plausible graphs are 1 and 3 since they are below the x-axis.
Now,

and

are only defined for x≥0, because only for these x'es we can take the square root.
Note that the third graph has domain (-infinity, 0], so it is not the right one, while 1 is ok.
Answer: first graph