The presidents in these years were: Jimmy Carter (1978), Ronald Reagan (1988), Bill Clinton (1998), Barack Obama (2008), and Donald Trump (2018). Please note that there are a variety of factors, not just the person holding the office of the president, that could influence these ratings; for example, the Great Recession occurred in 2008. However, for this exercise you will make a comparison of confidence in the executive branch without controlling for any other economic, social, political, and other processes that may influence these ratings.

When doing statistics, it is important to always consider whether there are other factors that may vary systematically with the independent variable. If the other factors vary randomly, they are not likely to confound results, but if they vary systematically with the independent variable, they will confound the findings. As you learned, ANOVA is rooted in experimental tradition, and correlation does not equal causation. We cannot randomly assign these persons to assume the presidential office at given times. (Can you imagine if the president were selected at random or assigned to serve in a randomly selected year?) So, although these results can provide insights, we must also consider their limits. Remember, statistics are important in making causal inferences, but statistical findings alone do not support causal inference. A fuller analysis would require considering and controlling for other factors that may be important.

Which of the following statements correctly reports the overallFtest result for this analysis?