Don’t know what the price of $137.70 is paying for. Do you have any dimensions?
f(x) = -5x^2 - x + 20;
f(3) = -5*3^2 - 3 + 20 = -5*9 - 3 + 20 = -45 - 3 + 20 = -28;
Answer:
The minimum sample needed to provide a margin of error of 3 or less is 52.
Step-by-step explanation:
The confidence interval for population mean (<em>μ</em>) is:

The margin of error is:

<u>Given:</u>
MOE = 3
<em>σ </em>= 11
The critical value for 95% confidence interval is: 
**Use the <em>z</em>-table for critical values.
Compute the sample size (<em>n</em>) as follows:

Thus, the minimum sample needed to provide a margin of error of 3 or less is 52.
Coefficient of variation is calculated by dividing the standard deviation by the mean multiplied by 100. Given a data set with mean equal to 60 and variance equal to 9, we can calculate the coefficient of variation by finding the value of the standard deviation which is the square root of the variance. so standard deviation is equal to square root of 9 which is 3. Then, the coefficient of variation is equal to 3/60*100 which is equal to 5%.