MATH 1280 Graded Quiz Unit 3 PDF

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MATH 1280 Graded Quiz Unit 3 There are 16 questions on this quiz. You will see a small group of questions at a time. Consider the following study: Marketing researchers Dominique and Huong wanted to know the following: “What percent of customers wear rain jackets at Seattle Food Store each day?” In an attempt to answer that question, Dominique and Huong designed a study. They called the store manager and arranged to collect data for 20 days. The researchers collected data for 4 hours each day for 20 days and counted the total number of shoppers who did and did not wear a rain jacket. The average number of customers per day who wore a rain jacket during the sample period was 32. 1. The population in this study was (read each answer and select the best one): c. All shoppers at the Seattle Food Store. 2. The sample in this survey was: b. The people who were observed shopping at the Seattle Food Store during the study. 3. How would you describe the possibility that the sample was biased (read all answers and select the best one): c. There could be bias because the selected days might not be representative of all the days (such as changing weather). Use this information for the next four questions: Researchers wanted to know about a standardized test that was used across the country. To get an estimate of the answer, they collected data from two classrooms of students who completed the test. Scores from Classroom A: 8, 6, 9, 9, 8, 7, 8, 9, 10, 8, 10, 5, 4, 10, 9, 9 Scores from Classroom B: 9, 8, 7, 8, 9, 10, 9, 10, 7, 8, 10, 9, 9, 4, 6, 3 4. The set of all scores on the standardized test across the country is: d. The population

5. When all the scores for the two classrooms are added and divided by the number of observations, the resulting value is a: a. a statistic 6. What is the mean score in Group A? c. 8.0625 7. Load data for Group B into an R object called B, then run this command: barplot(table(B)) What does the bar on the right represent? e. Three students received a score of 10 on the quiz.

Eighty adults with gum disease were asked the number of times per day they flossed. The (incomplete) results are shown below:

# per day

Freq.

Rel. Freq

0

15

.1875

1

21

.2625

2

18

.2250

3

Cum. Rel. Freq

.7875

4

9

.9000

5

8

1.000

Fill in the blanks in the table and answer the next two question:

8. The count of people who flossed three times per day is: d. 9 9. The cumulative relative frequency of those who flossed 0 to 2 times per day is: c. .6750

Use this information for the next six questions: category...