1. Identify the sampling technique used to obtain samples in the following situations (10 pts.)

RANDOM / STRATIFIED / CLUSTER / SYSTEMATIC / CONVENIENCE

a) Taking a survey of the first 50 students walking into the library.

b) Dividing a river into 20 regions and then randomly selecting 5 of the regions to test the cleanliness of the water.

c) Placing the names of every student in a hat and choosing 5 names for a group activity.

d) Selecting every 25^th can of soda on an assembly line to check for defects.

e) Dividing the customers of a ice cream parlor into age groups and asking each age group their personal preferences of flavors and toppings.

2. Test scores of 30 students are given below. Use this data for parts a - e of this question.

5570808590100

5575808590100

6075858590100

6080859095100

6580859095100

a) Construct a frequency distribution of the data collected. Use classes with the first class ranging from 51-60. (8 points)

b) Which one is(are) the modal class(es)? Circle the correct answer(s). (3 points)

a) 51 - 60b) 61 - 70c) 71 - 80d) 81 - 90e) 91 - 100

c) MAKE an histogram for the test scores using the same classes. (8 points)

d) MAKE a frequency polygon for the test scores using the same classes. (8 points)

e) MAKE a Stem-and-Leaf Display for the test scores of the 30 students. (8 points)

3. Determine the MEAN, MEDIAN, MODE, and MIDRANGE of the set of data below. Round answers to the nearest tenth when necessary. (12 pts)

60, 65, 70, 75, 75, 75, 80, 80, 80, 80, 90, 95, 100

Mean: _____Median: _____Mode: _____Midrange: _____

4. Determine the MEAN, MEDIAN, MODE, and MIDRANGE of the set of data below. Round answers to the nearest tenth when necessary. (12 pts)

9, 35, 31, 17, 19, 15, 35, 41, 13, 21, 25, 11

Mean: _____Median: _____Mode: _____Midrange: _____

5. Determine the Range and Standard Deviation of the set of data below. (8 points)

65, 70, 75, 80, 80, 85, 90, 90, 95, 100

6. Determine the Range and Standard Deviation of the set of data below. (8 points)

60, 58, 62, 67, 48, 51, 72, 70

7. A normal distribution has a mean of 25 and a standard deviation of 4. Determine z-scores for the following values. Round to the nearest tenth when necessary (3 points each):

a) 33b) 21 c) 15d) 39 e) 31

Answer: ___Answer: ___Answer: ___Answer: ___Answer: ___

EXTRA CREDIT: Refer to question #3 on the test.

Suppose a data value of 80 was added to the set of data. Determine how each of the following measures would be affected.

1. Mean:a) Increase b) Decrease c) Remain the same

2. Median: a) Increase b) Decrease c) Remain the same

3. Mode:a) Increase b) Decrease c) Remain the same

4. Midrange: a) Increase b) Decrease c) Remain the same