1.A researcher believes that attitudes about the police will shape how individuals feel about the black community. She uses two variables to test this hypothesis. First, her independent variable asks respondents whether Recent killings of African American men by police are either a) isolated incidents or b) part of a broader pattern. She then measures feelings about the black community with a feeling thermometer - it asks respondents to say how favorably they feel about the black community on a scale from 0 - 100. On this scale 0 is very unfavorable, 25 unfavorable, 50 no feeling at all, 75 favorable, and 100 very favorable. Respondents can provide any number from 0 to 100. For the purposes of this analysis, it is treated as an interval ratio variable. She hypothesizes that if a respondent believes these incidents are isolated incidents, they will score lower, on average, than those who see police shootings of African American's as part of a larger pattern.[Note - this is real data from a high-quality study conducted in 2016 and 2017]

a.What is the null hypothesis here?

b.Is there support for her research hypothesis? (Hint: Describe and Interpret the T-test below!)

c.Is there any reason we might be careful about the interpretation of this t-test?

d.Evaluate the null hypothesis.

T-Test Group Statistics Recent killings of African American men by police Std. Error in recent years are.. N Mean Std. Deviation Mean Feeling thermometer - Isolated incidents 3937 73.27 83.255 1.327 Blacks Part of a broader pattern 3164 87.19 89.790 1.596 Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means 95% Confidence Interval of the Mean Std. Error Difference Sig df Sig. (2-tailed) Difference Difference Lower Upper Feeling thermometer - Equal variances 1.697 .193 -6.760 7099 000 -13.918 2.059 -17.954 -9.882 Blacks assumed Equal variances not -6.705 6536.280 000 -13.918 2.076 -17.987 -9.849 assumed