1. In a survey, 40 people were asked how many times they visited a store before making a major purchase. The results are shown in Table 2.38.
Number of times in store | Frequency |
---|---|
1 | 4 |
2 | 10 |
3 | 16 |
4 | 6 |
5 | 4 |
Years since last purchase | Frequency |
---|---|
0 | 2 |
1 | 8 |
2 | 13 |
3 | 22 |
4 | 16 |
5 | 9 |
Number of TV Shows | Frequency |
---|---|
0 | 12 |
1 | 18 |
2 | 36 |
3 | 7 |
4 | 2 |
Seasons | Number of students | Proportion of population |
---|---|---|
Spring | 8 | 24% |
Summer | 9 | 26% |
Autumn | 11 | 32% |
Winter | 6 | 18% |
High School | Science competition population | Overall student population |
---|---|---|
Alabaster | 28.9% | 8.6% |
Concordia | 7.6% | 23.2% |
Genoa | 12.1% | 15.0% |
Mocksville | 18.5% | 14.3% |
Tynneson | 24.2% | 10.1% |
West End | 8.7% | 28.8% |
8. Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars. Complete the table.
Data Value (# cars) | Frequency | Relative Frequency | Cumulative Relative Frequency |
---|---|---|---|
What does the frequency column in Table 2.43 sum to? Why?
What does the relative frequency column in Table 2.43 sum to? Why?
What is the difference between relative frequency and frequency for each data value in Table 2.43?
What is the difference between cumulative relative frequency and relative frequency for each data value?
To construct the histogram for the data in Table 2.43, determine appropriate minimum and maximum x and y values and the scaling. Sketch the histogram. Label the horizontal and vertical axes with words. Include numerical scaling.
Construct a frequency polygon for the following:
-
Pulse Rates for Females Frequency 60–69 12 70–79 14 80–89 11 90–99 1 100–109 1 110–119 0 120–129 1 Table 2.44 -
Actual Speed in a 30 MPH Zone Frequency 42–45 25 46–49 14 50–53 7 54–57 3 58–61 1 Table 2.45 -
Tar (mg) in Nonfiltered Cigarettes Frequency 10–13 1 14–17 0 18–21 15 22–25 7 26–29 2 Table 2.46
Construct a frequency polygon from the frequency distribution for the 50 highest ranked countries for depth of hunger.
Depth of Hunger | Frequency |
---|---|
230–259 | 21 |
260–289 | 13 |
290–319 | 5 |
320–349 | 7 |
350–379 | 1 |
380–409 | 1 |
410–439 | 1 |
Use the two frequency tables to compare the life expectancy of males and females from 20 randomly selected countries. Include an overlayed frequency polygon and discuss the shapes of the distributions, the center, the spread, and any outliers. What can we conclude about the life expectancy of females compared to males?
Life Expectancy at Birth – Females | Frequency |
---|---|
49–55 | 3 |
56–62 | 3 |
63–69 | 1 |
70–76 | 3 |
77–83 | 8 |
84–90 | 2 |
Life Expectancy at Birth – Males | Frequency |
---|---|
49–55 | 3 |
56–62 | 3 |
63–69 | 1 |
70–76 | 1 |
77–83 | 7 |
84–90 | 5 |
Sex/Year | 1855 | 1856 | 1857 | 1858 | 1859 | 1860 | 1861 |
Female | 45,545 | 49,582 | 50,257 | 50,324 | 51,915 | 51,220 | 52,403 |
Male | 47,804 | 52,239 | 53,158 | 53,694 | 54,628 | 54,409 | 54,606 |
Total | 93,349 | 101,821 | 103,415 | 104,018 | 106,543 | 105,629 | 107,009 |
Sex/Year | 1862 | 1863 | 1864 | 1865 | 1866 | 1867 | 1868 | 1869 |
Female | 51,812 | 53,115 | 54,959 | 54,850 | 55,307 | 55,527 | 56,292 | 55,033 |
Male | 55,257 | 56,226 | 57,374 | 58,220 | 58,360 | 58,517 | 59,222 | 58,321 |
Total | 107,069 | 109,341 | 112,333 | 113,070 | 113,667 | 114,044 | 115,514 | 113,354 |
Sex/Year | 1870 | 1871 | 1872 | 1873 | 1874 | 1875 |
Female | 56,431 | 56,099 | 57,472 | 58,233 | 60,109 | 60,146 |
Male | 58,959 | 60,029 | 61,293 | 61,467 | 63,602 | 63,432 |
Total | 115,390 | 116,128 | 118,765 | 119,700 | 123,711 | 123,578 |
The following data sets list full time police per 100,000 citizens along with homicides per 100,000 citizens for a city during the period from 1961 to 1973.
Year | 1961 | 1962 | 1963 | 1964 | 1965 | 1966 | 1967 |
Police | 260.35 | 269.8 | 272.04 | 272.96 | 272.51 | 261.34 | 268.89 |
Homicides | 8.6 | 8.9 | 8.52 | 8.89 | 13.07 | 14.57 | 21.36 |
Year | 1968 | 1969 | 1970 | 1971 | 1972 | 1973 |
Police | 295.99 | 319.87 | 341.43 | 356.59 | 376.69 | 390.19 |
Homicides | 28.03 | 31.49 | 37.39 | 46.26 | 47.24 | 52.33 |
- Construct a double time series graph using a common x-axis for both sets of data.
- Which variable increased the fastest? Explain.
- Did the city's increase in police officers have an impact on the murder rate? Explain.
2.2 Measures of the Location of the Data
19. Listed are 29 ages for Academy Award winning best actors in order from smallest to largest.
18; 21; 22; 25; 26; 27; 29; 30; 31; 33; 36; 37; 41; 42; 47; 52; 55; 57; 58; 62; 64; 67; 69; 71; 72; 73; 74; 76; 77
- Find the 40th percentile.
- Find the 78th percentile.
18; 18; 21; 22; 25; 26; 27; 29; 30; 31; 31; 33; 36; 37; 37; 41; 42; 47; 52; 55; 57; 58; 62; 64; 67; 69; 71; 72; 73; 74; 76; 77
- Find the percentile of 37.
- Find the percentile of 72.
- For runners in a race, a low time means a faster run. The winners in a race have the shortest running times. Is it more desirable to have a finish time with a high or a low percentile when running a race?
- The 20th percentile of run times in a particular race is 5.2 minutes. Write a sentence interpreting the 20th percentile in the context of the situation.
- A bicyclist in the 90th percentile of a bicycle race completed the race in 1 hour and 12 minutes. Is he among the fastest or slowest cyclists in the race? Write a sentence interpreting the 90th percentile in the context of the situation.
- The 40th percentile of speeds in a particular race is 7.5 miles per hour. Write a sentence interpreting the 40th percentile in the context of the situation.
- Students' GPAs and scores on standardized tests (SATs and ACTs) are entered into a formula that calculates an "admissions index" score. The admissions index score is used to set eligibility standards intended to meet the goal of admitting the top 12% of high school students in the state. In this context, what percentile does the top 12% represent?
- Students whose GPAs are at or above the 96th percentile of all students at their high school are eligible (called eligible in the local context), even if they are not in the top 12% of all students in the state. What percentage of students from each high school are "eligible in the local context"?
Use the following information to answer the next six exercises. Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars.
Use the following information to answer the next two exercises. Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars.
2.3 Measures of the Center of the Data
-
Grade Frequency 49.5–59.5 2 59.5–69.5 3 69.5–79.5 8 79.5–89.5 12 89.5–99.5 5 Table 2.55 -
Daily Low Temperature Frequency 49.5–59.5 53 59.5–69.5 32 69.5–79.5 15 79.5–89.5 1 89.5–99.5 0 Table 2.56 -
Points per Game Frequency 49.5–59.5 14 59.5–69.5 32 69.5–79.5 15 79.5–89.5 23 89.5–99.5 2 Table 2.57
Use the following information to answer the next three exercises: The following data show the lengths of boats moored in a marina. The data are ordered from smallest to largest: 16; 17; 19; 20; 20; 21; 23; 24; 25; 25; 25; 26; 26; 27; 27; 27; 28; 29; 30; 32; 33; 33; 34; 35; 37; 39; 40
Use the following information to answer the next three exercises: Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars. Calculate the following:
41. median = _______
2.4 Sigma Notation and Calculating the Arithmetic Mean
Child | Rock colors |
1 | 5 |
2 | 5 |
3 | 6 |
4 | 2 |
5 | 4 |
6 | 3 |
7 | 7 |
8 | 2 |
9 | 1 |
10 | 10 |
Table 2.57
Child | Height in inches |
Adam | 45.21 |
Betina | 39.45 |
Chen | 43.78 |
Donna | 48.76 |
Edhas | 37.39 |
Fran | 39.90 |
George | 45.56 |
Heather | 46.24 |
Table 2.58
Price |
$20,987 |
$22,008 |
$19,998 |
$23,433 |
$21,444 |
Table 2.59
Weight in ounces |
15.65 |
16.09 |
16.01 |
15.99 |
16.02 |
16.00 |
15.98 |
16.08 |
Table 2.60
49. A city received the following rainfall for a recent year. What is the mean number of inches of rainfall the city received monthly, to the nearest hundredth of an inch? Use Table 2.61.
Month | Rainfall in inches |
January | 2.21 |
February | 3.12 |
March | 4.11 |
April | 2.09 |
May | 0.99 |
June | 1.08 |
July | 2.99 |
August | 0.08 |
September | 0.52 |
October | 1.89 |
November | 2.00 |
December | 3.06 |
Table 2.61
2.5 Geometric Mean
2.6 Skewness and the Mean, Median, and Mode
Use the following information to answer the next three exercises: State whether the data are symmetrical, skewed to the left, or skewed to the right.
65. Describe the shape of this distribution.
Figure 2.15
Figure 2.16
Figure 2.17
Figure 2.18
Figure 2.19
Figure 2.20
Figure 2.21
Figure 2.22
Figure 2.23
3; 4; 5; 5; 6; 6; 6; 6; 7; 7; 7; 7; 7; 7; 7
Is the data perfectly symmetrical? Why or why not?
11; 11; 12; 12; 12; 12; 13; 15; 17; 22; 22; 22
56; 56; 56; 58; 59; 60; 62; 64; 64; 65; 67
2.7 Measures of the Spread of the Data
Use the following information to answer the next two exercises: The following data are the distances between 20 retail stores and a large distribution center. The distances are in miles.
29; 37; 38; 40; 58; 67; 68; 69; 76; 86; 87; 95; 96; 96; 99; 106; 112; 127; 145; 150
Find the value that is one standard deviation below the mean.
Baseball player | Batting average | Team batting average | Team standard deviation |
---|---|---|---|
Fredo | 0.158 | 0.166 | 0.012 |
Karl | 0.177 | 0.189 | 0.015 |
Table 2.62
- above the mean
- below the mean
Find the standard deviation for the following frequency tables using the formula. Check the calculations with the TI 83/84.
-
Grade Frequency 49.5–59.5 2 59.5–69.5 3 69.5–79.5 8 79.5–89.5 12 89.5–99.5 5 Table 2.63
-
Daily low temperature Frequency 49.5–59.5 53 59.5–69.5 32 69.5–79.5 15 79.5–89.5 1 89.5–99.5 0 Table 2.64
-
Points per game Frequency 49.5–59.5 14 59.5–69.5 32 69.5–79.5 15 79.5–89.5 23 89.5–99.5 2 Table 2.65