Exam 4: A: Numerical Descriptive Techniques

$\sigma$ is a population parameter and s is a sample statistic.

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} Determine the location and value of the second quartile.

In a histogram,the proportion of the total area which must be to the left of the median is more than 0.50 if the distribution is positively skewed.

Computers The following data represent the number of computers owned by a sample of 10 families from Chicago: 4,2,1,1,5,3,0,1,0,and 2. -{Computers Narrative} Compute the median number of computers.

Expressed in percentiles,the fifth decile is the 50th percentile or the median.

Salaries of Employees The following data represent the yearly salaries (in thousands of dollars)of a sample of 13 employees 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 Employees Narrative} Compute the mean salary.

The line drawn within the box of a box plot always represents the median.

Ages of Workers The ages (in years)of three groups of workers are shown below: Group A: 17 22 20 18 23 Group B: 30 28 35 40 25 GroupC: 44 39 54 21 52 -{Ages of Workers Narrative} Compute and compare the coefficient of variation for the three samples.

The horizontal lines extending to the left and to the right of the box in a box plot are called ____________________.

The length of the box in a box plot portrays the interquartile range.

Which of the following types of data has no measure of variability?

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 range.

The value for Q₃ can never be smaller than the value for Q₁.

The ____________________ mean is used whenever we wish to find the "average" growth rate,or rate of change,in a variable over time.

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} Calculate the 3rd and 7th deciles of the data.

Chebysheff's Theorem states that the percentage of observations in a data set that should fall within five standard deviations of their mean is at least 96%.

Ages of Jockeys The following data represent the ages in years of a sample of 25 jockeys from a local race track: 31,43,56,23,49,42,33,61,44,28,48,38,44,35,40,64,52,42,47,39,53,27,36,35,and 20. -{Ages of Jockeys Narrative} Find the upper quartile of the ages.

Weights of Workers The following data represent the number of employees of a sample of 25 companies: 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 Workers Narrative} Find the median number of workers.

Suppose your data set contains ages (in years)and you calculate the range,variance,standard deviation,and coefficient of variation for the data.Explain what units each of these measures is in.

The ____________________ mean of n returns (or growth rates)is the appropriate mean to calculate if you wish to estimate the mean rate of return (or growth rate)for any single period in the future.