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A call center wants to optimize the number of staff available in the office to be able to guarantee a certain number of calls answered. In the data collection plan, data were collected about the number of calls answered per day(C5) during almost a year with varying staff availability (C6). Questions: Does the number of staff influence the calls answered/day? How many people should be present per day to guarantee 50 call answered in 95% of the cases? Tip: make fitted line plot with 95% prediction interval. Are the days of the week a stat. significant factor? Make a scatterplot with the regression staff/calls for each Day of the week as panel in one graph