solve the following activities

Page 7

Activity 1

Topic 1 – Organize your computer folders for this course

Complete the tasks:

1. Create a folder on your computer and name it MGSC 239 .

2. Add subfolders under the MIS 239 to keep your files organized. Here are some suggested subfolder names.

a. Activity 1

b. Activity 2

c. …..

Topic 2 – Access McGraw-Hill Connect Library for this course

1. Go to the Assignments section of our course on Blackboard.

2. Click on the McGraw-Hill connect Library link

a. Create an account or login to the Library for our course using your McGraw-Hill credentials.

b. Activate trial access or purchase access.

c. Activity 1

d. Activity 2

e. …..

Topic 3 – Download the eBook: Collaborative Statistics

1. Go to the Resources section of our course on Blackboard.

2. Download and save the Collaborative Statistics eBook to your computer

Review:

Key Terms

In statistics, we generally want to study a population . You can think of a population as an entire collection of persons, things, or objects under study. To study the larger population, we select a sample . The idea of sampling is to select a portion (or subset) of the larger population and study that portion (the sample) to gain information about the population. Data are the result of sampling from a population.

Because it takes a lot of time and money to examine an entire population, sampling is a very practical technique. If you wished to compute the overall grade point average at your school, it would make sense to select a sample of students who attend the school. The data collected from the sample would be the students’ grade point averages. In presidential elections, opinion poll samples of 1,000 to 2,000 people are taken. The opinion poll is supposed to represent the views of the people in the entire country. Manufacturers of canned carbonated drinks take samples to determine if a 16 ounce can contains 16 ounces of carbonated drink.

From the sample data, we can calculate a statistic . A statistic is a number that is a property of the sample. For example, if we consider one math class to be a sample of the population of all math classes, then the average number of points earned by students in that one math class at the end of the term is an example of a statistic. The statistic is an estimate of a population parameter. A parameter is a number that is a property of the population. Since we considered all math classes to be the population, then the average number of points earned per student over all the math classes is an example of a parameter.

One of the main concerns in the field of statistics is how accurately a statistic estimates a parameter. The accuracy really depends on how well the sample represents the population. The sample must contain the characteristics of the population in order to be a representative sample. We are interested in both the sample statistic and the population parameter in inferential statistics. In a later chapter, we will use the sample statistic to test the validity of the established population parameter.

A variable , notated by capital letters like X and Y, is a characteristic of interest for each person or thing in a population. Variables may be numerical or categorical. Numerical variables take on values with equal units such as weight in pounds and time in hours. Categorical variables place the person or thing into a category. If we let X equal the number of points earned by one math student at the end of a term, then X is a numerical variable. If we let Y be a person’s party affiliation, then examples of Y include Republican, Democrat, and Independent. Y is a categorical variable. We could do some math with values of X (calculate the average number of points earned, for example), but it makes no sense to do math with values of Y (calculating an average party affiliation makes no sense).

Data are the actual values of the variable. They may be numbers or they may be words. Datum is a single value.

Two words that come up often in statistics are average and proportion . If you were to take three exams in your math classes and obtained scores of 86, 75, and 92, you calculate your average score by adding the three exam scores and dividing by three (your average score would be 84.3 to one decimal place). If, in your math class, there are 40 students and 22 are men and 18 are women, then the proportion of men students is 22/40 and the proportion of women students is 18/40.

Example 1.1

Define the key terms from the following study: We want to know the average amount of money

first year college students spend at ABC College on school supplies that do not include books. We randomly survey 100 first year students at the college. Three of those students spent $150, $200, and $225, respectively.

Solution

The population is all first year students attending ABC College this term.

The sample could be all students enrolled in one section of a beginning statistics course at ABC College (although this sample may not represent the entire population).

The parameter is the average amount of money spent (excluding books) by first year college students at ABC College this term. The statistic is the average amount of money spent (excluding books) by first year college students in the sample.

The variable could be the amount of money spent (excluding books) by one first year student.

Let X = the amount of money spent (excluding books) by one first year student attending ABC College.

The data are the dollar amounts spent by the first year students. Examples of the data are $150, $200, and $225.

Activity 2

Topic 1 – Practice

Complete the tasks:

1. Form groups of 3 – 4 students and complete the following:

Example 1.5

Work collaboratively to determine the correct data type (quantitative or qualitative). Indicate whether quantitative data are continuous or discrete. Hint: Data that are discrete often start with the words "the number of."

1. The number of pairs of shoes you own

2. The type of car you drive

3. Where you go on vacation

4. The distance it is from your home to the nearest grocery store

5. The number of classes you take per school year

6. The tuition for your classes

7. The type of calculator you use

8. Movie ratings

9. Political party preferences

10. Weight of sumo wrestlers

11. Amount of money (in dollars) won playing poker

12. Number of correct answers on a quiz

13. Peoples’ attitudes toward the government

14. SAT scores.

Review:

A frequency is the number of times a given datum occurs in a data set. According to the table above, there are three students who work 2 hours, five students who work 3 hours, etc. The total of the frequency column, 20, represents the total number of students included in the sample.

A relative frequency is the fraction or proportion of times an answer occurs. To find the relative frequencies, divide each frequency by the total number of students in the sample - in this case, 20. Relative frequencies can be written as fractions, percents, or decimals.

Cumulative relative frequency is the accumulation of the previous relative frequencies. To find the cumulative relative frequencies, add all the previous relative frequencies to the relative frequency for the current row.

The following table represents the heights, in inches, of a sample of 100 male semiprofessional soccer players. Complete the table:

			RELATIVE
		RELATIVE	FREQUENCY
(INCHES)	FREQUENCY	FREQUENCY	CUMULATIVE
59.95 - 61.95	5
61.95 - 63.95	3
63.95 - 65.95	15
65.95 - 67.95	40
67.95 - 69.95	17
69.95 - 71.95	12
71.95 - 73.95	7
73.95 - 75.95	1

1. What are the class intervals?

2. How many class intervals are shown in the table.

3. Find the percentage of heights that are less than 65.95 inches.

4. Find the percentage of heights that fall between 61.95 and 65.95 inches.

Activity 3

Topic 1 – Stem and Leaf Display

One simple graph, the stem-and-leaf graph or stem plot, comes from the field of exploratory data analysis.It is a good choice when the data sets are small. To create the plot, divide each observation of data into a stem and a leaf. The leaf consists of a final significant digit. For example, 23 has stem 2 and leaf 3. Four hundred thirty-two (432) has stem 43 and leaf 2. Five thousand four hundred thirty-two (5,432) has stem 543 and leaf 2. The decimal 9.3 has stem 9 and leaf 3. Write the stems in a vertical line from smallest the largest. Draw a vertical line to the right of the stems. Then write the leaves in increasing order next to their corresponding stem.

For Dr. Smith’s spring MGSC 239 class, scores for the first exam were as follows (smallest to largest):

Complete the stem and leaf display.

Stem	Leaf
3
4
5
6
7
8
9
10

1. Are there any values that might possibly be outliers?

2. Do the data seem to have any concentration of values?

Review:

In a survey, 40 mothers were asked how many times per week a teenager must be reminded to do his/her chores. The results are shown in the table and the line graph.

Complete the table.

Number of times teenager is reminded	FREQUENCY
0
1
2
3
4
5

I was able to complete this activity successfully: Yes or No

Name _________________________________________ Date _________________