Study Notes on Decision Making Process in Statistics

Decision Making Process

• The decision-making process involves evaluating a claim, typically in a police context.
• This process can utilize two primary statistical methods:
  • Z-Test
  • Group Frequency Distribution

Finding the Mean

• To calculate the mean using group frequency distribution, follow these steps:
  1. Complete the Frequency Distribution Table: You will need to gather or have a set of data that contains frequencies and values.
  2. Determine the Midpoints: Midpoints can be calculated for the classes in the frequency distribution.
  3. Multiplication of Midpoints: For each class, multiply the midpoint by its frequency. This gives the weighted values.
  • Example: If a midpoint is 10 and the frequency is 3, then (10 imes 3 = 30).
  1. Square the Midpoints: Square each midpoint value and again multiply it by its frequency.
  • Example: If the midpoint is 10, then (10^2 imes 3 = 100 imes 3 = 300).
  1. Sum of Products: Add all the products from the previous step to obtain totals for further calculations.

Calculation of 'b'

• At this point, you would proceed to use the calculated sums (from midpoint products) to find a value referred to as 'b', which likely corresponds to a specific statistic or measure derived from frequencies and midpoints.

Exam Information

• It appears there are two questions based on the content discussed that will relate to these concepts as per Chapter Eight.
• Be prepared to apply the methods discussed (Z-Test and Group Frequency) to address possible exam questions involving statistical evaluation.