Exam 3: Describing Data Using Numerical Measures

When surveyed, a sample of 1,250 patients at a regional hospital provided interviewers with the following summary statistics pertaining to the hospital charges: Minimum = $278.00 Q1 = $1,245 Q2 = $3,567 Q3= $4,702. Based on these data, if you were to construct a box and whisker plot, the value corresponding to the right-hand edge of the box would be $4,702.

The following sample data reflect electricity bills for ten households in San Diego in March. Compute the range, variance, and standard deviation for these sample data. Discuss which of these three measures you would prefer to use as a measure of variation.

Suppose a study of houses that have sold recently in your community showed the following frequency distribution for the number of bedrooms: Based on this information the mean number of bedrooms in houses that sold is approximately 3.26.

The right and left edges of the box in a box and whisker plot represent the 3rd and 1st quartiles, respectively.

Dynamic random-access memory (DRAM) memory chips are made from silicon wafers in manufacturing facilities through a very complex process called wafer fabs. The wafers are routed through the fab machines in an order that is referred to as a recipe. The wafers may go through the same machine several times as the chip is created. The data file DRAM Chips contains a sample of processing times, measured in fractions of hours, at a particular machine center for one chip recipe. Determine what the mode processing time is.

If the age distribution of customers at a major retail chain is thought to be bell-shaped with a mean equal to 43 years and a standard deviation equal to 7 years, the percentage of customers between the ages of 29 and 57 years is:

A small company has 7 employees. The numbers of years these employees have worked for this company are shown as follows: Based upon this information, the median number of years that employees have been with this company is:

A distribution has a coefficient of variation of 65 percent and mean of 74. What is the value of the standard deviation?

One of the reasons that the standard deviation is preferred as a measure of variation over the variance is that the standard deviation is measured in the original units.

Todd Lindsey & Associates, a commercial real estate company located in Boston, owns six office buildings in the Boston area that it leases to businesses. The lease price per square foot differs by building due to location and building amenities. Currently, all six buildings are fully leased at the prices shown here. Compute the weighted average (mean) price per square foot for these buildings.

Consumer products are required by law to contain at least as much as the amount printed on the package. For example a bag of potato chips that is labeled as 10 ounces should contain at least 10 ounces. Assume that the standard deviation of the packaging equipment yields a bag weight standard deviation of 0.2 ounces. Explain what average bag weight must be used to achieve at least 97.5 percent of the bags having 10 or more ounces in the bag. Assume the bag weight distribution is bell-shaped.

Suppose a study of houses that have sold recently in your community showed the following frequency distribution for the number of bedrooms: Based on this information, the mode for the data is 140.

When surveyed, a sample of 1,250 patients at a regional hospital provided interviewers with the following summary statistics pertaining to the hospital charges: Minimum = $278.00 Q1 = $1,245 Q2 = $3,567 Q3= $4,702. Based on these data, if you were to construct a box and whisker plot, the value $278 would be considered an outlier.

A store manager tracks the number of customer complaints each week. The following data reflect a random sample of ten weeks. The variance for these data is approximately 27.78.

The symbol μ is used to represent the sample mean.

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership. Given these data, what is the range?

Consider a situation involving two populations where population 1 is known to have a higher coefficient of variation than population 2. In this situation, we know that population 1 has a higher standard deviation than population 2.

If a data set has 1,133 sorted values, what value corresponds to the 3rd quartile?

The range is an ideal measure of variation since it is not sensitive to extreme values in the data.

Consider the following data, which represent the number of miles that employees commute from home to work each day. There are two samples: one for males and one for females. Which of the following statements is true?