Statistics - Week 3 HW Questions

The histogram to the right represents the weights​ (in pounds) of members of a certain​ high-school math team. What is the class​ width? What are the approximate lower and upper class limits of the first​ class?

The class width is 10. The approximate lower class limit is 100. The approximate upper class limit is 110. * The approximate lower class limit of the first class is the first approximate lower class limit found above​ (approximately 100). * The upper class limit of the first class is approximately equal​ to the second lower class​ limit of 110. * Therefore, the approximate lower and upper class limits of the first class are 100 and 110, respectively.

The given data represents a frequency distribution of the​ F-scale intensities of recent tornadoes. Use the frequency distribution to construct a frequency polygon. Does the graph suggest that the distribution is​ skewed? If​ so, how?

The distribution appears to be skewed to the right (or positively skewed). *긴 꼬리가 오른쪽 방향으로 늘어지고 있다=skewed to the right=positively skewed

The accompanying data set lists diastolic blood pressure measurements​ (mm Hg) of females. All of the values are even numbers. Construct a stemplot. Identify the two values that are closest to the middle when the data are sorted in order from lowest to highest.​ (These values are often used to find the​ median.)

6 0466888 7 00022666 8 0444688 9 04 The two values that are closest to the middle when the data are sorted in order from lowest to highest are 72 and 76. * Since there are 24 data​ values, the two values closest to the middle of the ordered list would be the 12th and 13th data values.

A study was conducted to determine how people get jobs. The table lists data from 400 randomly selected subjects. Construct a Pareto chart that corresponds to the given data. If someone would like to get a​ job, what seems to be the most effective​ approach?

Hep-wanted ads (H)

Here are 6 celebrities with some of the highest net worths​ (in millions of​ dollars) in a recent​ year: George Lucas (5500​), Oprah Winfrey (3200​), Michael Jordan ​(1700​), J. K. Rowling (1000​), David Copperfield (1000​), and Jerry Seinfeld (950​). Find the​ range, variance, and standard deviation for the sample data. What do the results tell us about the population of all​ celebrities? Based on the nature of the​ amounts, what can be inferred about their​ precision?

Range= 4550 Variance= 3,315,750 Standard deviation= 1821 What do the results tell us about the population of all​ celebrities? Because the data are from celebrities with the highest net​ worths, the measures of variation are not at all typical for all celebrities. Based on the nature of the​ amounts, what can be inferred about their​ precision? Because all of the amounts end with 0, it appears that they are rounded to the nearest ten million dollars,so it would make sense to round the results to the nearest million dollars.

Below are the jersey numbers of 11 players randomly selected from a football team. Find the​ range, variance, and standard deviation for the given sample data. What do the results tell​ us? 29 43 80 18 71 56 67 30 59 62 65

Range= 62 Sample standard deviation= 19.9 (use StatCrunch) Sample variance= 394.8 (use StatCrunch) What do the results tell​ us? Jersey numbers are nominal data that are just replacements for​ names, so the resulting statistics are meaningless.

A study was conducted to determine how people get jobs. The table below lists data from 400 randomly selected subjects. Compare the pie chart found above to the Pareto chart given on the left. Can you determine which graph is more effective in showing the relative importance of job​ sources?

The Pareto chart is more effective

The table below shows the frequency distribution of the weights​ (in grams) of​ pre-1964 quarters. Use the frequency distribution to construct a histogram. Does the histogram appear to depict data that have a normal​ distribution? Why or why​ not?

The histogram appears to depict a normal distribution. The frequencies generally increase to a maximum and then​ decrease, and the histogram is roughly symmetric.

The histogram to the right represents the weights​ (in pounds) of members of a certain​ high-school math team. How many team members are included in the​ histogram?

The histogram represents 10 math team members.

Listed below are the numbers of hurricanes that occurred in each year in a certain region. The data are listed in order by year. Find the​ range, variance, and standard deviation for the given sample data. Include appropriate units in the results. What important feature of the data is not revealed by any of the measures of​ variation? 10 2 6 15 15 17 13 1 20 18 3 9 6 7

The range of the sample data is 1919 hurricanes. The standard deviation of the sample data is 6.2 hurricanes. The variance of the sample data is 39.1 hurricanes^2. What important feature of the data is not revealed through the different measures of​ variation? The measures of variation reveal nothing about the pattern over time.

The data represents the heights of eruptions by a geyser. Use the heights to construct a stemplot. Identify the two values that are closest to the middle when the data are sorted in order from lowest to highest.

The values closest to the middle are 60 inches and 62 inches. * Since there are 20 data​ values, the two values closest to the middle of the ordered list would be the 10th and 11th data values.

The accompanying data represent​ women's median earnings as a percentage of​ men's median earnings for recent years beginning with 1989. Is there a​ trend? How does it appear to affect​ women? Construct a​ time-series graph.

There is a general upward trend though there have been some down years. An upward trend would be helpful to women so that their earnings become equal to those of men.

Find the​ (a) mean,​ (b) median,​ (c) mode, and​ (d) midrange for the data and then​ (e) answer the given questions. Listed below are the highest amounts of net worth​ (in millions of​ dollars) of all celebrities. What do the results tell us about the population of all​ celebrities? Based on the nature of the​ amounts, what can be inferred about their​ precision? 230 190 175 160 150 150 130 130 130 130

a. mean: 157.5 b. median: 150 c. mode: 130 d. midrange: 180 e. What do the results tell us about the population of all​ celebrities? Apart from the fact that all other celebrities have amounts of net worth lower than those​ given, nothing meaningful can be known about the population. f. Based on the nature of the​ amounts, what can be inferred about their​ precision? The values all end in 0 or​ 5, so they appear to be rounded estimates.

Find the​ (a) mean,​ (b) median,​ (c) mode, and​ (d) midrange for the data and then​ (e) answer the given question. Listed below are the jersey numbers of 11 players randomly selected from the roster of a championship sports team. What do the results tell​ us? 51 15 58 3 39 78 62 38 19 32 74

a. mean: 42.6 b. median: 39 c. mode: there is no mode d. midrange: 40.5 e. What do the results tell​ us? The jersey numbers are nominal data and they do not measure or count​ anything, so the resulting statistics are meaningless.

Find the​ (a) mean,​ (b) median,​ (c) mode, and​ (d) midrange for the given sample data. An experiment was conducted to determine whether a deficiency of carbon dioxide in the soil affects the phenotype of peas. Listed below are the phenotype codes where 1=smooth-yellow​, 2=smooth-green​, 3=wrinkled-yellow​, and 4=wrinkled-green. Do the results make​ sense? 4 4 4 4 3 1 3 1 4 3 1 2 4 1

​(a) The mean phenotype code is 2.8. ​(b) The median phenotype code is 3. ​(c) Select the correct choice below and fill in any answer boxes within your choice. The mode phenotype code is 4. (d) The midrange of the phenotype codes is 2.5. (f) Do the measures of center make​ sense? Only the mode makes sense since the data is nominal.