QNT/275: Statistics For Decision Making
LUUP777
Week2HomeworkProblemsPost.xlsx1
In a hearing test, subjects estimate the loudness (in decibels) of a sound, and the results are: 69, 67, 71, 72, 65, 75, 68, 68, 83, 73, 68. Calculate the measures of central tendency (Mean, median, mode) and the measures of dispersion (range, standard deviation, variance).
2
The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stopwatch to record the time they spent in line. The times recorded were as follows (in minutes). 117, 123, 110, 117, 99, 120, 148, 118, 119, 120, 45, 130, 118 What is the 72d percentile?
3
The average life of Canadian women is 73.90 years, and the standard deviation of the life expectancy of Canadian women is 9 years. Based on Chebyshev's Theorem, determine the upper and lower bounds on the average life expectancy of Canadian women such that at least 95 percent of the population is included if the sample size is 100 women.
4
The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stopwatch to record the time they spent in line. The times recorded were as follows (in minutes): 118, 121, 114, 116, 110, 120, 145, 118, 119, 121, 45, 135, 118. Calculate the measures of central tendency (Mean, median, mode) and the measures of dispersion (range, standard deviation, variance).
5
The average lateness for one of the top airline companies is 10 minutes. The variance of the lateness measure is calculated as 8. An airplane arrived 12 minutes after the stated arrival time. Calculate the z-score for the lateness of this particular airplane.
6
According to a survey of the top 15 employers in a major city in the Midwest, a worker spends an average of 400 minutes a day on the job. Suppose the standard deviation is 20 minutes and the time spent is approximately a normal distribution. What are the times within which approximately 99.73 percent of all workers will fall?
7
| Female | Male | |
| Correctly Recalled the company | 65 | 53 |
| Incorrectly recalled the company | 35 | 47 |
Recently an advertising company called 200 people and asked them to identify the company that was in an ad running nationwide. The following results were obtained. What percentage of those surveyed could not correctly recall the company?
8
| Credit Balance | LED | LCD | Plasma | Projection |
| Under $200 | 10 | 10 | 45 | 5 |
| $200 - $800 | 8 | 17 | 20 | 15 |
| Over $800 | 16 | 10 | 16 | 30 |
A local electronics retailer recently conducted a study on purchasers of large screen televisions. The study recorded the type of television and the credit account balance of the customer at the time of purchase. They obtained the following results. What percentage of purchases were plasma televisions by customers with the smallest credit balances?
9
| Grade | Rel Fx |
| A | 0.25 |
| B | |
| C | 0.25 |
| D | 0.2 |
| F | 0.08 |
The following is a partial relative frequency distribution of grades in an introductory statistics course. Find the relative frequency for the B grade.
10
A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. What would be the class length used in creating a frequency histogram?
