BQA 3123 Iva Ballard Exam 1

BQA 3123 Iva Ballard Exam 1central tendency a statistical measure to determine a single score that defines the center of a distribution; the most typical or most representative value Mean The average of a set of numbers Median the middle score in a distribution; half the scores are above it and half are below it Mode the most frequently occurring score(s) in a distribution; Issues with mean Can be influenced by outliers Issues with Mode Some data sets may not have one. Can be influenced by outliers Range measure of variability, spread, dispersion Max-Min Limitations of Range only uses Minimum and Maximum values. Considers only 2 values Two reasons to use a Z-Score -Tells you the exact location of the raw score within distribution -Allows us to compare with other distributions due to standardization Properties of Z-Scores -The shape of the distribution of the z-score will be the same as the shape of the distribution of the raw scores -Mean on z-scores = 0 -Standard Deviation = 1 Conditions needed for a valid large sample Confidence Interval -A random sample is selected from the target population. -The sample size is greater than or equal to 30 -Due to the CLT, this condition guarantees that the sampling distribution of X-bar is approx. normal