Exam 4: Numerical Descriptive Techniques

Which of these measures of central location is not sensitive to extreme values?

Hours Worked per Week ​ The following data represent the hours worked per week of a sample of 25 employees from a government department: 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. ​ ​ -{Hours Worked per Week Narrative} Compute the sample mean hours.

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 lower quartile of the ages.

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 mean number of computers.

The ____________________ of a linear relationship is hard to interpret from the covariance,but it is easy to interpret from the correlation.

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.

If ,n = 12,and the slope equals 0.5,then the y-intercept of the least squares line is b₀ = 276.08.

Hours Worked per Week ​ The following data represent the hours worked per week of a sample of 25 employees from a government department: 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. ​ ​ -{Hours Worked per Week Narrative} Compare the mean and median hours for these employees and use them to discuss the shape of the distribution.

The Empirical Rule states that the percentage of observations in a data set (providing that the data set is bell shaped)that fall within one standard deviation of their mean is approximately 75%.

The Y-intercept,b₀,of the least squares line represents the:

The size of a sample is denoted by the letter ____________________ and the size of a population is denoted by the letter ____________________.

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} Construct a relative frequency distribution for the data,using five class intervals and the value 20 as the lower limit of the first class.

The median of an ordered data set with 30 items would be the average of the 15^th and the 16^th observations.

When the standard deviation is expressed as a percentage of the mean,the result is the coefficient of correlation.

The mean of a sample of 15 measurements is 35.6 feet.Suppose that the sample is enlarged to 16 measurements,by including one additional measurement having a value of 42 feet.Find the mean of the sample of the 16 measurements.

The y-intercept of the least squares line is the point on the line when ________________ = 0.

The least squares method minimizes which of the following sum of squares?

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

According to the Empirical Rule,if the data form a bell shaped normal distribution approximately ____________________ percent of the observations will be contained within 3 standard deviations around the mean.

If a data set is composed of 5 different numbers,there are ____________________ modes.