Methods of Demonstrating Reliability of Measurement - Essay Example

When the results predict a higher retest coefficient or high positive correlation then the test would be reliable. Multiple-form reliability refers to the application of equivalent forms of measure and correlation. This measurement tool is similar to test-retest reliability, but in this, subjects are given both forms of measure concurrently. Split-half reliability reflects the correlation between the two halves in a set of items but the coefficient varies, depending on how the scale is split. Sometimes when more than one scale, dimension, or factor is evaluated split-half reliability is used to check the consistency (Sekaran, 2006).

Q No.2 What are the two types of crime seriousness scales and what utility are they in criminal justice research?

Ans. Crime seriousness scales are the severity scales that judge the seriousness of the crime based on the weights assigned to them. There are two types of crime seriousness scales, simple rating scales and magnitude scales. Simple rating scales determine the rate of crime based on scales ranging from 1(not serious) to 9 (extremely serious). However, this rating scale is unable to determine the magnitude difference between the scale scores. While the magnitude scale measures the degree of seriousness of various crimes by public ranking. Selling-wolf gang index and the national survey of crime severity are two examples of magnitude scales in crime seriousness. Both these crime seriousness scales are used in criminal justice research to determine and analyze the seriousness of the crime. Crime seriousness scales not only judge the crime level but also help in controlling (Wilmot, 2002).

Q No.3 Explain the least-square regression line.

Ans. The least square regression line is known as the best-fitted line, least square line, regression line, and least square prediction equation. It represents a mathematical model for a group of data. Generally, linear regression consists of finding the best-fitted line through the points in the scatter diagram. This line identifies the relationship between a single predictor variable X and the response variable Y, while the other predictor variables are held fixed. This regression line is also used to predict the value of y for a given value of x, i.e. it is used in prediction and forecasting. It is a line that minimizes the distance of the actual scores from the predicted scores. The least square regression line is determined by the formulas

Y=A+BX, where A is the y-intercept and B determines the slope of the least square line (McClave & Dietrich, 1988).

Q No. 4 How do you use the regression line for prediction?

Ans.  A regression line can be used for future prediction and forecasting sales or other forecast projects. The regression line shows the trend line for long-term movements in time series data where the independent variable X, estimates the dependent variable Y for the future or next period. Due to this, we can easily predict the value of Y based on certain values of X. The Regression line is generally plotted on the scatter plot of independent and dependent variables because they fall on a perfect line. The regression line is the best-fitted line due to this it gives an accurate knowledge of past trends and even future trends.