You should make a bar graph to compare pieces of data rather than identifying a trend. Also, you should always use a bar graph if there will be words on the x or horizontal axis.
You should make a line graph when you are looking for a pattern, trend, or to study changes over time.
You should make a scatterplot when you have paired numerical data; when you collect 2 pieces of information for each data point.
How to add text labels to the horizontal and vertical axis, as well as a chart title.
Add a trendline when you need a straight line through your data to show a pattern of increasing or decreasing values.
How to get the right information on each axis.