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Construct the outlier boxplot for the exam scores of 13 students in your statistics class: 48, 55, 63, 68, 75, 76, 76, 78, 78, 81, 87, 89, 93. Write a complete description of the analysis of the exam score data. Remember that a complete description of numerical data includes comments on shape, center, and spread.
Minimum: 48, Ist Quartile: 68, Median: 76, 3rd Quartile: 81, Maximum:94) IQR = 13 with step 19.5 Lower Fence = 48.5 and Upper Fence = 100.5 Lower Adjacent Value = 55 Upper Adjacent Value = 93 Outlier at 48 *The distribution of statistics student’s exam scores is slightly skewed left or to the low values. A typical score on the test was 76 points, the median. The overall variability of the exam scores is 45 points with the middle half of the data having a spread of 13 points. These is one outlier at the low end of 48 points.
A survey of enrollment at 35 community colleges across the United States yielded the following figures ( source: Microsoft Bookshelf ):
The median age of the U.S. population in 1980 was 30.0 years. In 1991, the median age was 33.1 years. ( Source: Bureau of the Census )
The following box plot shows the U.S. population for 1990, the latest available year. (Source: Bureau of the Census, 1990 Census)
The next three questions refer to the following information. We are interested in the number of years students in a particular elementary statistics class have lived in California. The information in the following table is from the entire section.
| Number of years | Frequency |
|---|---|
| Total = 20 | |
| 7 | 1 |
| 14 | 3 |
| 15 | 1 |
| 18 | 1 |
| 19 | 4 |
| 20 | 3 |
| 22 | 1 |
| 23 | 1 |
| 26 | 1 |
| 40 | 2 |
| 42 | 2 |
What is the IQR?
A
What is the mode?
A
Is this a sample or the entire population?
B
The next two questions refer to the following table. = the number of days per week that 100 clients use a particular exercise facility.
| x | Frequency |
|---|---|
| 0 | 3 |
| 1 | 12 |
| 2 | 33 |
| 3 | 28 |
| 4 | 11 |
| 5 | 9 |
| 6 | 4 |
The 80th percentile is:
D
The number that is 1.5 standard deviations BELOW the mean is approximately:
A
The next two questions refer to the following histogram. Suppose one hundred eleven people who shopped in a special T-shirt store were asked the number of T-shirts they own costing more than $19 each.
The percent of people that own at most three (3) T-shirts costing more than $19 each is approximately:
C
If the data were collected by asking the first 111 people who entered the store, then the type of sampling is:
D
Below are the 2010 obesity rates by U.S. states and Washington, DC. ( Source: http://www.cdc.gov/obesity/data/adult.html) )
| State | Percent (%) | State | Percent (%) |
|---|---|---|---|
| Alabama | 32.2 | Montana | 23.0 |
| Alaska | 24.5 | Nebraska | 26.9 |
| Arizona | 24.3 | Nevada | 22.4 |
| Arkansas | 30.1 | New Hampshire | 25.0 |
| California | 24.0 | New Jersey | 23.8 |
| Colorado | 21.0 | New Mexico | 25.1 |
| Connecticut | 22.5 | New York | 23.9 |
| Delaware | 28.0 | North Carolina | 27.8 |
| Washington, DC | 22.2 | North Dakota | 27.2 |
| Florida | 26.6 | Ohio | 29.2 |
| Georgia | 29.6 | Oklahoma | 30.4 |
| Hawaii | 22.7 | Oregon | 26.8 |
| Idaho | 26.5 | Pennsylvania | 28.6 |
| Illinois | 28.2 | Rhode Island | 25.5 |
| Indiana | 29.6 | South Carolina | 31.5 |
| Iowa | 28.4 | South Dakota | 27.3 |
| Kansas | 29.4 | Tennessee | 30.8 |
| Kentucky | 31.3 | Texas | 31.0 |
| Louisiana | 31.0 | Utah | 22.5 |
| Maine | 26.8 | Vermont | 23.2 |
| Maryland | 27.1 | Virginia | 26.0 |
| Massachusetts | 23.0 | Washington | 25.5 |
| Michigan | 30.9 | West Virginia | 32.5 |
| Minnesota | 24.8 | Wisconsin | 26.3 |
| Mississippi | 34.0 | Wyoming | 25.1 |
| Missouri | 30.5 |
Example solution for b using the random number generator for the Ti-84 Plus to generate a simple random sample of 8 states. Instructions are below.
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