713 A health psychologist, concerned about the increase in skin cancer, conducted a study to determine whether people thought a person looked healthier with a suntan compared to no suntan. Twenty participants were randomly assigned to either view a photograph of an individual with a suntan or view the same picture of the person without a suntan. Computer software was used to darken or lighten the person's skin. After viewing the photograph, participants indicated their perceptions of the individual's health on a scale of 1 (not very healthy- looking) to 7 (very healthy-looking). Data for this hypothetical study are shown below. Use this data to answer questions 19 through 24. Photograph With Suntan ( X. ) Without Suntan ( X 2 ) ANWNAWONW - VOADAUINWOA 19. State the null and research hypotheses. Null hypothesis: Research hypothesis: 20. State whether this is a one-tailed or two-tailed hypothesis. (Circle one) One-tailed Two-tailed 21. Calculate the degrees of freedom and find the critical value from Table T. df =