AMU MATH 120 Intro to statistics Homework week 1 American Military University

Assistance for AMU MATH 120 Intro to statistics Homework week 1 American Military University is available at Domyclass

1. Are data at the nominal level of measurement quantitative or qualitative?

• Qualitative
• both quantitative and qualitative
• quantitative
• neither quantitative nor qualitative

2.What is the difference between a parameter and a statistic?

• A parameter is an aspect of an individual subject or object being measured. A statistic is a numerical measurement describing data from a sample.

• A parameter is a numerical measurement describing data from a population. A statistic is a numerical measurement describing data from a sample.

• A parameter is a numerical measurement describing data from a population. A statistic is an aspect of an individual subject or object being measured.

• A parameter is an aspect of an individual subject or object being measured. A statistic is a numerical measurement describing data from a population.

• A parameter is a numerical measurement describing data from a sample. A statistic is an aspect of an individual subject or object being measured.

• A parameter is a numerical measurement describing data from a sample. A statistic is a numerical measurement describing data from a population.

3. What is the average miles per gallon (mpg) for all new hybrid small cars? Using Consumer Reports, a random sample of such vehicles gave an average of 35.7 mpg.

(a) Identify the variable.

• new hybrid small cars
• miles per gallon
• all cars
• total miles

(b) Is the variable quantitative or qualitative?

• quantitative
• both quantitative and qualitative
• qualitative

(c) What is the implied population?

• all cars with average miles per gallon
• all new hybrid small cars
• all cars
• the new hybrid cars that were examined

4. Categorize these measurements associated with student life according to level: nominal, ordinal, interval, or ratio.

(a) Length of time to complete an exam

• nominal
• ordinal
• interval
• ratio

(b) Time of first class

• nominal
• ordinal
• interval
• ratio

(c) Major field of study

• nominal
• ordinal
• interval
• ratio

(d) Course evaluation scale: poor, acceptable, good

• nominal
• ordinal
• interval
• ratio

(e) Score on last exam (based on 100 possible points)

• nominal
• ordinal
• interval
• ratio

(f) Age of student

• nominal
• ordinal
• interval
• ratio

5. Explain the difference between a simple random sample and a systematic sample. (Select all that apply.)

• In a simple random sample, every sample of size n has an equal chance of being included. In a systematic sample, the only samples possible are those including every kth item from the random starting position.

• In a simple random sample, the clusters to be included are selected at random and then all members of each selected cluster are included.

• In a simple random sample, the only samples possible are those including every kth item from the random starting position.

• In a simple random sample, random samples from each strata are included.

• In a systematic sample, random samples from each strata are included.

• In a systematic sample, the clusters to be included are selected at random and then all members of each selected cluster are included.

• In a systematic sample, every sample of size n has an equal chance of being included.

6. Modern Managed Hospitals (MMH) is a national for­profit chain of hospitals. Management wants to survey patients discharged this past year to obtain patient satisfaction profiles. It wishes to use a sample of such patients. Several sampling techniques are described below. Categorize each technique as simple random sample, stratified sample, systematic sample, cluster sample, or convenience sample.

(a) Obtain a list of patients discharged from all MMH facilities. Divide the patients according to length of hospital stay (2 days or less, 3­7 days, 8­14 days, more than 14 days). Draw simple random samples from each group.

• simple random sample
• stratified sample
• systematic sample
• cluster sample
• convenience sample

(b) Obtain lists of patients discharged from all MMH facilities. Number these patients, and then use a random­number table to obtain the sample.

• simple random sample
• stratified sample
• systematic sample
• cluster sample
• convenience sample

(c) Randomly select some MMH facilities from each of five geographic regions, and then include all the patients on the discharge lists of the selected hospitals.

• simple random sample
• stratified sample
• systematic sample
• cluster sample
• convenience sample

(d) At the beginning of the year, instruct each MMH facility to survey every 500th patient discharged.

• simple random sample
• stratified sample
• systematic sample
• cluster sample
• convenience sample

(e) Instruct each MMH facility to survey 10 discharged patients this week and send in the results.

• simple random sample
• stratified sample
• systematic sample
• cluster sample
• convenience sample

7. Which technique for gathering data (sampling, experiment, simulation, or census) do you think was used in the following studies?

(a) An analysis of a sample of 31,000 patients from New York hospitals suggests that the poor and the elderly sue for malpractice at one­fifth the rate of wealthier patients. ( Journal of the American Medical Association).

• Sampling
• Experiment
• Simulation
• census

(b) The effects of wind shear on airplanes during both landing and takeoff were studied by using complex computer programs that mimic actual flight.

• sampling
• experiment
• simulation
• census

(c) A study of all league football scores attained through touchdowns and field goals was conducted by the National Football League to determine whether field goals account for more scoring events than touchdowns (USA Today).

• sampling
• experiment
• simulation
• census

(d) An Australian study included 588 men and women who already had some precancerous skin lesions. Half got skin cream containing a sunscreen with a sun protection factor of 17; half got an inactive cream. After 7 months, those using the sunscreen with the sun protection had fewer precancerous skin lesions (New England Journal of Medicine).

• Sampling
• Experiment
• Simulation
• Census

8. A data set with whole numbers has a low value of 20 and a high value of 103. (For each answer, enter an exact number.)

Find the class width for a frequency table with seven classes.

Find the class limits for a frequency table with seven classes.

9. How long does it take to finish the 1161­mile Iditarod Dog Sled Race from Anchorage to Nome, Alaska? Finish times (to the nearest hour) for 57 dogsled teams are shown below.

261 271 236 244 279 296 284 299 288 288 247 256 338 360 341 333 261 266 287 296 313 311 307 307 299 303 277 283 304 305 288 290 288 289 297 299 332 330 309 328 307 328 285 291 295 298 306 315 310 318 318 320 333 321 323 324 327 For this problem, use five classes.

(a) Find the class width. (Enter an exact number.)

(b) Make a frequency table showing class limits, class boundaries, midpoints, frequencies, relative frequencies, and cumulative frequencies.

(c) Draw a histogram. (Select the correct graph.)

(d) Draw a relative­frequency histogram. (Select the correct graph.)

(e) Categorize the basic distribution shape.

• bimodal
• skewed right
• skewed left
• mound­shaped symmetrical
• uniform

(f) Draw an ogive. (Select the correct graph.)

10. A personnel office is gathering data regarding working conditions. Employees are given a list of five conditions that they might want to see improved. They are asked to select the one item that is most critical to them. Which type of graph, circle graph or Pareto chart, would be the most useful for displaying the results of the survey? Why?

• Circle chart, because it shows the total number of important issues to employees.
• Pareto chart, because it shows the items in order of importance to employees.
• Pareto chart, because it shows the total number of important issues to employees.
• Circle chart, because it shows the items in order of importance to employees.

11. How do college professors spend their time? The National Education Association Almanac of Higher Education gives the following average distribution of professional time allocation: teaching, 53%; research, 16%; professional growth, 4%; community service, 11%; service to the college, 11%; and consulting outside the college, 5%. Make a pie chart showing the allocation of professional time for college professors. (Select the correct graph.)

12. The American Medical Association Center for Health Policy Research included data, by state, on the number of community hospitals and the average patient stay (in days) in its publication State Health Care Data: Utilization, Spending, and Characteristics. The data (by state) are shown in the table.

Average No. of Length State Hospitals of Stay Alabama 119 7 Alaska 16 5.7 Arizona 61 5.5 Arkansas 88 7 California 440 6 Colorado 71 6.8 Connecticut 35 7.4 Delaware 8 6.8 D.C. 11 7.5 Florida 227 7 Georgia 162 7.2 Hawaii 19 9.4 Idaho 41 7.1 Illinois 209 7.3 Indiana 113 6.6 Iowa 123 8.4 Kansas 133 7.8 Kentucky 107 6.9 Louisiana 136 6.7 Maine 38 7.2 Maryland 51 6.8 Massachusetts 101 7 Michigan 175 7.3 Minnesota 148 8.7 Mississippi 102 7.2 Missouri 133 7.4 Montana 53 10 Nebraska 90 9.6 Nevada 21 6.4 New Hampshire 27 7 New Jersey 96 7.6 New Mexico 37 5.5 New York 231 9.9 N. Carolina 117 7.3

N. Dakota 47 11.1 Ohio 193 6.6 Oklahoma 113 6.7 Oregon 66 5.3 Pennsylvania 236 7.5 Rhode Island 12 6.9

S. Carolina 68 7.1

S. Dakota 52 10.3 Tennessee 122 6.8 Texas 421 6.2 Utah 42 5.2 Vermont 15 7.6 Virginia 98 7 Washington 92 5.6

W. Virginia 59 7.1 Wisconsin 129 7.3 Wyoming 27 8.5 Make a stem­and­leaf display of the data for the average length of stay in days. (Use the digit(s) to the left of the decimal point as the stem and the digit to the right as the leaf.)

Comment about the general shape of the distribution.

• The distribution is bimodal.

• The distribution is skewed right.

• The distribution is uniform.

• The distribution is skewed left.