1. An engineering firm conducts traffic studies on behalf ofcompanies that want to build a new store in Miami, Florida. Theaverage cost of these traffic studies is $15,500, and the standarddeviation for these costs is $4,250. These costs have a bell-shapeddistribution. What is the approximate percentage of these trafficstudies that will cost between $2,750 and $19,750?
Enter your answer as a decimal rounded to twoplaces.
2. Calculate the sample variance for the following set of datafrom a coffee shop. The values represent the amount of money (indollars) the cash register is short or over after eight randomlyselected shifts: -0.72, 0.42, 1.14, -0.81, -0.13, -0.10, -0.17, and1.19.
Sample variance =Â Â dollars2
3. The median for a left-skewed distribution is 68.5.Which of the statements below are correct?
You must make a selection for each option. Click once toplace a check mark for correct answers and click twice to empty thebox for the wrong answers.
| The mode is more than 68.5. |
| The mean is less than 68.5. |
| The mean is more than 68.5. |
| The mean is also 68.5. |
4.
The mean income of a group of sample observations is $500; thestandard deviation is $40. According to Chebyshev’s theorem, atleast what percent of the incomes will lie between $400 and $600?(Omit the \"%\" sign in your response.) |
| Â Â Percent of the incomes | % |
5.
Consider these five values of a population: 7, 3, 6, 3, and6. |
| (a) | Determine the mean of the population. (Round your answerto 1 decimal place.) |
| (b) | Determine the variance of the population. (Round youranswer to 2 decimal places.) |
