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KING FAHD UNIVERSITY OF PETROLEUM & MINERALS
DEPARTMENT OF MATHEMATICAL SCIENCES
DHAHRAN, SAUDI ARABIA
STAT 211: BUSINESS STATISTICS
Major Exam 1, Semester-051 (2005)
Time: 9:00 pm to 10:30 pm. Thursday, October 13, 2005.
Instructors: Musawar Amin Malik, Mohammad H. Omar
Student Name: ID# Section #
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Answer all questions. You are allowed to use any electronic calculator.
Question No / Marks / Marks Obtained1-10 / 10
11-17 / 7
18 / 22
19 / 5
20 / 3
21 / 8
22 / 20
Total / 75
Part I. State True or False. (10 points).
1. A sales manager has seven salesmen. The following are the number of Xerox copier machines sold by these salesmen during the past week: {5, 7, 12, 13, 6, 2, 4}. Based on the data, the mean number of machines sold was 6.
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2. Typically, it is possible to include a larger number of questions in a phone survey than in a mail survey since it takes less time to complete the survey over the phone.
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3. Assuming that you are planning to collect data using an experiment, it will be very important to establish an appropriate survey design.
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4. Data collected using open-ended questions is generally easier to analyze than data collected from closed-ended questions.
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5. When the marketing manager for a large company surveys a portion of the total customers of his company, he is using a sample from the population.
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6. Statistics are measures computed from the entire population of data.
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7. The Bank of Riyadh mailed out a survey to all 11,456 savings account customers. A total of 1568 surveys were returned. Values computed from the returned surveys would constitute parameters since all customers were surveyed.
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8. When stratified random sampling is employed, the population is divided into intact subgroups called strata and only certain strata are sampled.
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9. When students are asked to list their age and the percentage of their college expenses that they pay for themselves, the type of data being collected is quantitative.
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10. A group of 30 customers surveyed in front of Farm 5 does not constitute a statistical sample from the population of Farm 5 customers.
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Part II. Circle the best answer to the questions below. (7 points).
11. When the park ranger at Yellowstone National Park reports the average length of time that visitors spend in the park, he is using:
a. graphical tools.
b. numerical measures.
c. statistical charts.
d. histograms or bar charts.
12. Data that are collected from the entire population are referred to as:
a. primary data.
b secondary data.
c. a census.
d. a sample.
13. Which of the following data collection methods is most likely to generate the largest non-response?
a. Mail surveys.
b. Direct observation.
c. Telephone surveys.
d. Personal interviews.
14. When an accounting auditor randomly selects 20 accounts from all the accounts to check for accuracy, she has selected:
a. a personal observation.
b. a sample from the population.
c. a census.
b. a convenience sample.
15. If a manager at Al-Bilad company wishes to randomly survey a population, but would like to be able to reduce the required sample size compared to what would be needed if the simple random sampling method was used, which method might be effective?
a. Stratified random sampling.
b. Nonstatistical sampling.
c. Convenience sampling.
d. All of the above.
16. A value computed from a population is called:
a. a statistic.
b. a real number.
c. a parameter.
d. a point estimate.
17. The following are the steps to conduct a written survey except
a. designing the survey.
b. determining the sample size and sampling method.
c. defining the population of interest.
d. calling the participants to ensure they respond to survey.
Part III. Solving Questions
18. Suppose you are given the following data.
(10+2+5+5 points).
a. Make a frequency table for the above data with starting point 80 and a class width 8.
b. What is the relative frequency of the highest frequency class?
18. Suppose you are given the following data.
c. Make a frequency histogram and comment on the shape of the distribution.
d. Make a stem-and-leaf plot for the above data.
19. Recently a study of fans attending the New York Mets baseball games was conducted. One of the variables for which data were collected from the 500 fans surveyed was the miles from home to the stadium. The data for this variable were formulated into 5 classes and a frequency distribution was developed. The first class contained 247 fans and was for those traveling between 0 and 5 miles. Based on this information (3+2 points).
a. What was the relative frequency for the first class?
b. What is the measurement level for this data?
20. The asking price for homes on the real estate market in Baltimore has a mean value of $286,455 and a standard deviation of $11,200. Based on this, find a standardized value of a home with an asking price of $203,400. (3 points).
21. The following data reflect the number of customers who return merchandise for a refund on Monday. Note these data reflect the population of all 10 Mondays for which data are available. (5+3 points).
a. Calculate the mean, median and mode for this data.
b. Calculate the 70th percentile and interpret this value.
22. The following sample data reflect electricity bills for ten households in San Diego in March.
(7+6+3+4 points).
a. Determine three measures of central tendency for these sample data. Then, based on these measures, determine whether the sample data are symmetric or skewed (left or right).
b. Compute the range, variance, and standard deviation for these sample data.
22. The following sample data reflect electricity bills for ten households in San Diego in March.
c. Determine the coefficient of variation and interpret your result.
d. Does this data satisfy the 95% condition of the Empirical Rule? Why?