Answer:
Mean = 1.42
Variance = 0.58
Step-by-step explanation:
Given: X denote the number of luxury cars sold in a given day, and Y denote the number of extended warranties sold.
Also, joint probability function of X and Y are given.
To find:
mean and variance of X
Solution:
From the given joint probability function of X and Y,

Mean of X:

Variance of X:

![var(X)=E\left [ X^2 \right ]-\left ( E\left [ X \right ] \right )^2\\=\frac{31}{12}-\left ( \frac{17}{12} \right )^2\\=\frac{31}{12}-\frac{289}{144}\\=\frac{372-289}{144}\\=\frac{83}{144}\\=0.58](https://tex.z-dn.net/?f=var%28X%29%3DE%5Cleft%20%5B%20X%5E2%20%5Cright%20%5D-%5Cleft%20%28%20E%5Cleft%20%5B%20X%20%5Cright%20%5D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cleft%20%28%20%5Cfrac%7B17%7D%7B12%7D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cfrac%7B289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B372-289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B83%7D%7B144%7D%5C%5C%3D0.58)
You can find counterexamples to disprove this claim. We have positive integers that are perfect square numbers; when we take the square root of those numbers, we get an integer.
For example, the square root of 1 is 1, which is an integer. So if y = 1, then the denominator becomes an integer and thus we get a quotient of two integers (since x is also defined to be an integer), the definition of a rational number.
Example: x = 2, y = 1 ends up with
which is rational. This goes against the claim that
is always irrational for positive integers x and y.
Any integer y that is a perfect square will work to disprove this claim, e.g. y = 1, y = 4, y= 9, y = 16. So it is not always irrational.
Answer:
0.2(y-2)
Step-by-step explanation:
factor out 1/5 from the expression
1/5×(y-2)
0.2(y-2)
Question 1: D
Question 2:D
Question 3: C
Question 4: A
Question 5: D
Answer:
Tyrone paid the higher markup rate.
Step-by-step explanation:
Tyrone and Terri both bought sofas with installment loans.
Tyrone bought his own with a sticker price of $1350 by paying $74 a month for 24 months. Therefore,
74 × 24 = $1776
The mark up = $1776 - $1350 = $426
Tyrone markup rate = 426/24 = $17.75 per month
Terri bought his own with sticker price of $950 by paying $52 a month for 24 months. Therefore,
52 × 24 = $1248
mark up = $1248 - $950 = $298
Terri markup rate = 298/24 = $12.4166666667 = $12.42 per month