Measures of Location

• The mean calculation in a grouped table is:

  
  

  $\overline{x}$ = $\frac{\sum_{ }^{ }fx}{\sum_{ }^{ }f}$
• To find the position of the quartiles in ordered, listed data, take which number?

  $Q_1$ : $\frac{n}{4}$

  $Q_2$ : $\frac{n}{2}$

  $Q_3$ : $\frac{3n}{4}$
• If finding quartiles in listed data, if the number is decimal, how do you treat non-whole numbers?

  round up
• How would you calculate which number is the 57th percentile over n values for grouped data? Take the $0.57\times n$ th number
• How would you calculate the 3rd Decile?

  
  

  $D_3$ = $P_{30}$ = $0.3\ \times n$
• What do you not do while calculating percentiles or deciles?

  round
• What do you use for grouped data to handle percentiles and deciles?

  linear interpolation
• In this example, what are the true class limits?

  A) 9.5

  B) 12.5

  C) 12.5

  D) 15.5