Chapter 4 - Displaying and Summarizing Quantitative Data

1) Bar graphs are used to display categorical data, while histograms are used to display quantitative data. Also, bars do NOT touch in bar graphs, but they do touch in histograms.

2a) When you describe a distribution, you should ALWAYS tell about three things: its shape, center, and spread.

2b) While talking about the shape of a distribution you should look if the histogram has any humps, or in other words modes. A histogram with one peak is called unimodal,  histograms with two peaks are called bimodal, and histograms with three or more are called multimodal. Another thing to look for is to see if the histogram is symmetric, if there are any outliers that stand ot from the rest of the data, and  notice if the histogram is skewed either to the right or left.

The center of the distribution can either be literally at the center of the distribution if it is unimodal symmetrical distribution, but if not it is known as the median, which is the middle value that divides the histogram into two equal areas.

When talking about the spread of the data it is important to note the range of the data, which is defined as the difference between the maximum and minimum values. The interquartile range (IQR) is the difference between the upper quartile and lower quaritile that tells us how much territory the middle half of the data covers.

3) Average Height by Teenagers by frequency
a)  5 Number Summary:
       Max: 8
       Q3:
       Median:
      Q1:
      Min.:

3b) Mean:
Standard Deviation:

3c)  

The graph appears to be unimodal,as it has one peak at 130 to 134. The graph also appears to be symmetrical because if we were to fold it in half it would match up appropriately.