X≈2.48207399,<span>−<span>2.14874066</span></span>
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)
Solution: Estimated time for the work is 40 hour work week.
Estimated payment to 3 laborers working 40 hours at cost $14 per hour is:
$1680
Estimated payment to 6 masons working 40 hours at cost $24 per hour is:
$5760
Estimated cost of material = $3143
Contractor wishes to make a profit of $500
Therefore, the mathematical expression that will give the estimated cost of the job is:

The estimated total cost is:
Cost =$11083
Answer:
8
Step-by-step explanation:
To find the mean, or average of a data set, add all the values together, then divide by the number of values.
The data set is: 6,7,9,9,9
1. Add all the values
Add 6,7,9,9 and 9
6+7+9+9+9
40
2. Divide by the number of values
Count how many numbers are in the data set. In this case, there are 5 numbers.
Divide 40 by 5.
40/5
8
The mean of the data set is 8.
Solution:

Answer:

<em>Hope this was helpful.</em>