270 likes | 473 Views
CHAP 17 CHI ( Kahy ) SQURE. PARAMETRIC AND NONPARAMETRIC STATISTICAL TESTS. PARAMETRIC tests are more accurate than NONPARAMETRIC tests because they have 3 assumptions ( research). 1. Random selection 2. Independent of observation
E N D
PARAMETRIC AND NONPARAMETRIC STATISTICAL TESTS • PARAMETRIC testsare more accurate than NONPARAMETRIC tests because they have 3 assumptions (research). • 1. Random selection • 2. Independent of observation • 3. Sample is taken from a normal population with a normal distribution
NONPARAMETRIC STATISTICAL TESTS • CHI SQURE is like frequency distribution (Chap 2) • It is used for comparative studies. • Ex1. Of the two leading brands of cola, which is preferred by most Americans?
CHI SQURE • Ex2. which psychotherapy technique is used by most psychologists? i.e. cognitive, behavioral, humanistic, CBT, psychodynamics, etc.
CHI SQURE • = Σ(fo-fe)²/fe • fo= observed frequency • fe= expected frequency • df = C-1 • C= number of categories fe = n/c = Ho n= sample size
Problems • Distribution of Eye colors for a sample of n=40 individuals. • FYI From chapter 2 Frequency Distribution • (X )eye colors (f ) frequencies • Blue 12 • Brown 21 • Green 3 • Other 4 see next slide for Chi square
Problems • Distribution of Eye colors for a sample of n=40 individuals. • Frequency distribution Fo
The question for the hypothesis test is whether there are any distribution of the four possible eye colors. Are any of the eye color distribution would be expected simply by chance? We will set alpha at α =.05 • Step 1) H0 : fo = fe no preference for any specific eye color H1 : fo ≠ fe preference for specific eye color
Problems • Distribution of Eye colors for a sample of n=40 individuals. • Frequency distribution fo fe
Problems • A psychologist examining art appreciation selected an abstract painting that had no obvious top or bottom. Hangers were placed on the painting so that it could be hung with any one of the four sides at the top. The painting was shown to a sample of n=50 participants, and each was asked to hung the painting in the orientation that looked correct. The following data indicate how many people choose each of the four sides to be placed at the top. • fo
Problems • The question for the hypothesis test is whether there are any preferences among the four possible orientations. Are any of the orientations selected more (or less) often than would be expected simply by chance? • We will set alpha at α =.05
Problems • Step 1) H0 : fo=feno preference for any specific orientation H1 : fo≠fepreference for specific orientation
Problems • A researcher is using a chi-square test for independence to examine the relationship between TV preferences and gender for a sample of n = 100 children. Each child is asked to select his/her favorite from a fixed set of three TV shows and each child is classified as male or female. The chi-square statistic for this study would have df equal to ?