Question

1. The paper "How Happy Was I, AnywayT A Retrospective Impact Bla" (Social Cognition (2003): 421-446) reported on a experiment designed to assess the extent to which people rationalize poor performance. In this study, 246 college undergraduntes were assigned at random to one of two groupe - a negative feedback group OF A positive feedback group. Each participant took a test in which they were asked to guess the emotions displayed in photographs of faces. At the end of the test, those in the negative feedback group were told that they had correctly unawered 21 of the 40 items and were assigned a "grade" of D. Those in the positive feedback group were told that they had answered 35 out of 40 correctly and were assigned an A grade. After a brief times, participants were asked to answer two sets of questions. One set of questions asked about the validity of the test and the other set of questions asked about the importance of being able to read face. The researchers hypothesized that those in the negative feedback group would tend to rationalize their poor performance by rating both the validity of the test and the importance of being a good face reader lower than those in the positive feedback group. Size Test validity Rating Face Reading Impactance Rating Sample Standard Standard Group Mean Teristian Mean Deviation Negative feedback 123 5.51 79 5.36 1.00 Positive feedback 123 6.95 1.09 6.62 1.19 (a) (3 pointsIs there convincing evidence that those in the negative feedback group would also not rate the Importance of being able to read faces as highly as those in the positive group? Use a significance level of .05, round your test statistic to the appropriate amount of decimal places to use the correct chart, and round everything else to 4 decimal places using the seven-step process learned in class. 1. Describe what the population characteristics are measuring: 3. Significance level a = 2 H 4. Assumptions: A.; B. + 5. Which test statistic should we use for this hypothesis test? Calculate the test statistic:

Answer 1

Solo - Given, (a), use the significance level of .05 round your dest statistic to the appropriate amount of de cimal places to use the connect chant else tou decimal places, (1). Here what n,=123 the population characteristics are measuring I, = 5.36 Si=1.00 n2 = 123 X2 = 6.62 52 = 1.19 (2). Ho: Mi-M, 20 Hail, M₂ 70 20.05 (3). significance leveld L-005 4). Assumptions is. Dependent variable must be contions (ii) obserations are andependent of one another (11) should be oppleximately nosimally distribution I should not contain any otheries,

(5). Test statistic should we use for this hypothesis test calcelate the dest statistic we wse Z-dest bothn, & m2 230 z = xinh Spa (no-ins +(12-1) 57 Meth₂-2 s (123-171.19 +(123-1)).197 1 123+ 123-2 (122) 1.41614 (122) 1.4161 sp=1 23 +123 -2 172.7642 + 172.7642 246.2 sp= 3u5.5284 1 zuu SP=81.n16i sp= 1.99

(6). calculate degree of freedom we do not need degree of freedom (7) conclusion Critical z at 2=0.05 is 1.96 we relect Ho af z4-1.96 or z21.96 Hence here to as rejected P-value c 6.0000 interval for the difference construct confidence in mean scores of the face reading importance. confidence interval for difference between two means. con.fidence interval os (-44738,1.653 796)

(C) conclusion sendence stating confidence internal mean. confidence interval for differene in mean provideces an estimate of obstute diffeence. in mean of outcome varuble of interest between comparison groups. (d). Is zero include confidence Interval in the mean. Zero is the null value of of difference in meam, if Parameter in the case. confidence interval includes significant difforent the null value. Statistically between groups,