Qualitative or Quantitative Variable: What's the Difference?

Question 1 

Identify whether the variable in the information below is qualitative or quantitative. Government agencies carefully monitor water quality and its effect on wetlands (Reference: Environment Protection Agency Wetland Report EPA 832-R-93-005). Of particular concern is the concentration of nitrogen in water draining from fertilized lands. Too much nitrogen can kill fish and wildlife. Twenty-eight samples of water were taken at random from a lake. The nitrogen concentration (milligrams of nitrogen per liter of water) was determined for each sample. 

A. quantitative 

Question 2 

Wetlands offer a diversity of benefits. They provide habitat for wildlife, spawning grounds for U.S. commercial fish, and renewable timber resources. In the last 200 years, the United States has lost more than half its wetlands. Suppose Environmental Almanac gives the percentage of wetlands lost in each state in the last 200 years as noted in the table below 

  The distribution of the percentage loss of wetlands per state is approximately mound shaped. 

False 

Question 3 

In a biology class, the final grade is based on several things: a lab score, score on two major tests, and the score on the final exam. There are 100 points available for each score. However, the lab score is worth 30% of your total grade, each major test is worth 22.5%, and the final exam is worth 25%. Compute the weighted average for the following scores: 90 on the lab, 82 on the first significant test, 91 on the second major test, and 84 on the final exam. Round your answer to the nearest hundredth. 

D. 86.92 

Question 4 

Finish times (to the nearest hour) for 59 dogsled teams are provided. Draw a relative frequency histogram. Use five classes. 261 270 236 244 278 296 284 297 287 287 250 256 338 360 341 333 261 267 287 296 313 311 309 309 299 303 277 283 304 305 286 290 286 287 297 299 332 330 309 329 309 329 285 291 295 298 306 315 310 318 318 320 333 321 323 324 327 302 319 

Class limits	Boundaries	Midpoint	frequency	Relative frequency	Cumulative frequency
236-260	235.5-260.5	248	4	0.07	4
261-285	260.5-285.5	273	9	0.15	13
286-310	285.5-310.5	298	26	0.44	39
311-335	310.5-335.5	323	17	0.29	56
336-360	335.5-360.5	348	3	0.05	59

Question 5 

Given the sample data, 13, 32, 28, 13, 12, 23, compute the sample standard deviation. 

8.71  

Question 6 

Given the values of x: 24, 17, 12, 34, and 28, find the sample variance. Round your answer to the nearest hundredth and place it in the blank. For example, 62.70 is a legitimate answer.    

Sample variance is 76.00 

Question 7 

Let. x be a random variable representing an annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). Given data for the past several years, compute the coefficient of variation for each fund, round your answers to the nearest tenth. 

X	15	0	38	23	35	25	26	-15	-15	-23
Y	10	-2	27	18	24	18	18	-2	-3	-10

Coefficient of variation = 

Coefficient of variation X = 

Coefficient of variation Y =  hence, 

for x-values: 205.5%, and for y-values: 133.2% 

Question 8 

At Center Hospital, there is some concern about the high turnover of nurses. A survey was done to determine how long (in months) nurses had been in their current positions. The responses (in months) of 20 nurses were generated. Using the procedure specified by Brase and Brase, find the interquartile range, rounded to one decimal place. 

27	3	7	20	28	38	31	45	19	11
9	11	35	30	33	16	25	37	13	38

Q1 = 12 

Q3 = 34 

Interquartile range = Q3-Q1 

Interquartile range = 34-12 = 22.0 

hence, 

22.0 

Question 9 

Given box plots for the annual premium for urban customers in three states, which state has the smallest range of premiums for urban customers?

D. Pennsylvania has the smallest range of premiums.  

Question 10 

Given box plots for the annual premium for urban customers in three states, which state has the highest median premium for urban customers?

D. California has the highest median premium.