Exam 4: A: Numerical Descriptive Techniques

Weights of Teachers The following data represent the weights in pounds of a sample of 25 teachers: 164,148,137,157,173,156,177,172,169,165,145,168,163,162,174,152,156,168,154,151,174,146,134,140,and 171. -{Weights of Teachers Narrative} Compute the sample variance and sample standard deviation.

According to the Empirical Rule,if the data form a bell shaped normal distribution,approximately ____________________ percent of the observations will be contained within 2 standard deviations around the mean.

The distance between the 25th percentile and the median is always the same as the distance between the median and the 75th percentile.

{Strip Mall Rent Narrative} What is the mode?

Which of the following summary measures cannot be easily approximated from a box plot?

The median of a set of data is more representative than the mean when the mean is larger than most of the observations.

Hours of Playing Video Games Suppose that the following data provide the hours of playing video games per week for a sample of 15 high school students in Roanoke,Virginia: 5,11,25,19,18,20,27,13,8,10,15,19,18,9,and 12. -{Hours of Playing Video Games Narrative} Calculate and interpret the interquartile range.

Weights of Police Officers The following data represent the weights in pounds of a sample of 25 police officers: 164,148,137,157,173,156,177,172,169,165,145,168,163,162,174,152,156,168,154,151,174,146,134,140,and 171. -{Weights of Police Officers Narrative} Describe the shape of the distribution of weights based on the quartiles' values.

Yearly Donations The following data represent the yearly donations (in thousands of dollars)of a sample of 13 benefactors: 26.5,23.5,29.7,24.8,21.1,24.3,20.4,22.7,27.2,23.7,24.1,24.8,and 28.2. -{Yearly Donations Narrative} Compute median.

In a negatively skewed distribution,the distance from the smallest observation to Q₁ exceeds the distance from Q₃ to the largest observation.

Which of the following statements about the median is not true?

Test Scores Suppose that an analysis of a set of test scores reveals that: Q₁ = 45,Q₂ = 85,Q₃ = 105. -{Test Scores Narrative} What do these statistics tell you about the shape of the distribution of test scores?

Another word for the mean of a data set is the ____________________.

A population with 200 elements has a variance of 20.From this information,it can be shown that the population standard deviation is 10.

The length of the box in the box plot portrays the:

The value of the mean times the number of observations equals the sum of the observations.

{Strip Mall Rent Narrative} Compute the sample median.

Salaries of Office Workers The following data represent the salaries (in thousands of dollars)of a sample of 13 office workers of a firm: 26.5,23.5,29.7,24.8,21.1,24.3,20.4,22.7,27.2,23.7,24.1,24.8,and 28.2. -{Salaries of Office Workers Narrative} Compute the variance and standard deviation of the salaries,and express the numbers in the appropriate units.

In a bell shaped distribution,there is no difference in the values of the mean,median,and mode.

In a perfectly symmetric distribution,which of the following statements is false?