For an IF function to check whether cell B3 contains a value between 15 and 20 inclusively, what condition should you use?

pie chart  line chart  XY scatter chart  bar chart[...]

 In the Format group, select Trendline from the Insert Shapes list.  Click outside the plot area and select Add Trendline[...]

 =COUNT(B4:E4&G4:I4)  =COUNT(B4:E4,G4:I4)  =COUNT(B4:E4 G4:I4)  =COUNT(B4:I4)[...]