Test Name: Exam #2a Practice

1. Consider the following data:

Step 1. Find the value of the mean.

Step 2. Find the value of the median.

Step 3. Select the number of modes and indicate the modes if any. Separate multiple modes with commas.

2. Consider the following data:

Step 1. Find the value of the sample variance. Round your answer to one decimal place.

Step 2. Find the value of the sample standard deviation. Round your answer to one decimal place.

Step 3. Find the value of the range.

3. Find the 10% trimmed mean of the following data. Use the rounding rules for calculating the trimmed mean.

MLB Batting Averages

0.275 / 0.278 / 0.279 / 0.281 / 0.287 / 0.289 / 0.290 / 0.293 / 0.295 / 0.296
0.301 / 0.301 / 0.302 / 0.307 / 0.307 / 0.308 / 0.309 / 0.314 / 0.317 / 0.324

4. Calculate the sample standard deviation for the following data set. Use the rounding rule for standard deviation.

Slugging Percentages for Leading Major League Baseball Players
0.646 / 0.589 / 0.532 / 0.625 / 0.649
0.561 / 0.551 / 0.651 / 0.524 / 0.647
0.570 / 0.584 / 0.635 / 0.628 / 0.671
0.663 / 0.548 / 0.635 / 0.663 / 0.529

5. Consider the following sets of sample data:

A: 3.41, 3.98, 4.01, 3.53, 3.52, 3.81, 4.57, 4.26, 4.66, 2.92, 4.14, 3.38, 4.29, 3.57

B: $2.00, $2.51, $2.27, $2.49, $1.89, $2.48, $2.09, $2.53, $1.96, $2.20, $1.81

Step 1. For each of the above sets of sample data, calculate the coefficient of variation, CV.

Step 2. Which of the above sets of sample data has the smaller spread?

6. Suppose that salaries for recent graduates of one university have a mean of with a standard deviation of . Using Chebyshev's Theorem, state the range in which at least of the data will reside. Please do not round your answers.

7. A sample of 139 motels is selected from a large urban area and the price for a night of lodging for a single room was determined for each motel. The mean rate is computed to be $98 and the standard deviation is $14. One motel charged $59 per night which is the 12 percentile. Another motel charged $116 per night which is the 75 percentile.

Step 1. What is the -score for a motel charging $106 per night? ( Round your answer to 2 decimals )

Step 2. How many motels charged at least $116 per night? Round your answer to the nearest integer.

Step 3. How many motels charged at least $59 per night? Round your answer to the nearest integer.

Step 4. If the -score for a motel is , what is the price of a single room at the motel (in dollars)?

Step 5. The median rate is at most $59.

8. Calculate the interquartile range of the given data.

7, 38, 3, 42, 21, 38, 51, 40, 55, 30, 28, 41, 48, 18

9. Evaluate the following expression.

10. You decide to record the hair colors of people leaving a lecture at your school. What is the probability that the next person who leaves the lecture will have red hair? Express your answer as a simplified fraction or a decimal rounded to three decimal places.

Blonde / Red / Brown / Black / Gray
25 / 30 / 37 / 20 / 31

11. A coin is tossed 3 times. What is the probability that the number of tails obtained will be 3? Write your answer as a fraction or a decimal number rounded to three decimal places.

12. There are 72 students in a physics class. The instructor must choose two students at random.

Students in a Physics Class
Males / Females
Freshmen / 3 / 13
Sophomores / 4 / 13
Juniors / 3 / 19
Seniors / 14 / 3

What is the probability that a junior male and then a senior female are chosen at random? Write your answer as a fraction or a decimal number rounded to three decimal places.

13. Determine whether the following value could be a probability.

14. Decide if the following probability is classical, empirical, or subjective.

This type of probability is found by experiment.

15. What is the probability that a randomly selected person will have a birthday in October? Assume that this person was not born in a leap year. Express your answer as a simplified fraction or a decimal rounded to three decimal places.

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