Constructing boxplots to compare male and female pulse rates

Intro

Howdy!  I'm Professor Curtis of Aspire Mountain Academy here with more statistics homework help.  Today we're going to learn how to construct box plots to compare male and female pulse rates.  Here's our problem statement: Use the same scales to construct box plots for the pulse rates of males and females from the company data sets.  Use the box plots to compare the two data sets.

Part 1

OK, the first part of this problem is asking us for a box plot for the men's pulse rate.  So to do that, we need to access the data.  So I'm going to click on this icon here, and here's all of the data that we need to look at for this problem.  We'll click on this icon so I can dump the data into StatCrunch.

OK, here we've got the data here in StatCrunch, so now we need to make our box plot.  And to do that I'm going to come up here to Graph --> Box Plot.  In the options window, I'm going to select the column for the men's pulse rate.  But I know that the problem is also going to ask me to get a box plot for the women's pulse rates.  So let's just make both of them now while we're here.

Then down here amongst the other options, I'm going to check the box for Draw boxes horizontally.  That's because the box plots that are here in my assignment are drawn in the horizontal orientation.  I don't know why this isn't a default selection because all of the box plots that I've ever saw working in the real world were drawn with the horizontal orientation.  So yeah, I don't know why the default is the vertical, but it is what it is.  We'll check the box, and we'll get what we need.

And that's all we need.  There's lots of other options you could select, but all we need for our purposes is what we've selected already.  So I'm going to hit Compute!, and then here in my results window, I got these wonderful box plots.

Now to help us compare the box plot that we've drawn here in StatCrunch with the options that were listed here in our assignment, what I'm going do is I'm going to change the scale of my x-axis so we're comparing apples with apples.  So to do that, I'm going to click on this little three bar symbol in the left lower corner of my results window.  And in the menu that appears, I'm going to select the x-axis, and I'm going to change the minimum to what we see here with the graph in the assignment.  All the minimum values here for the graphs are 40, and all the maximums you see are 110.  So I'm going to change those settings.  So now I'm comparing apples with apples and it's easier for me to see which is the actual correct answer.  And after doing that, it seems pretty obvious for the men it's going to be Answer option D.  Good job!

Part 2

Now the second part asks for the women's box plot, which we just made before or during the previous part.  Notice the scales here are the same.  So we don't need to make any adjustment down here.  And so now all that remains is to select the correct answer, which looking at our different options answers and comparing them, it looks like this is going to be the correct one.  Excellent!

Part 3

And now the last part asks us to compare the two box plots.  Well, this is the advantage we have of making both of them at the same time, because now that one is overlaying the other, it makes it easier to compare the two box plots.  So looking at the general location, it seems like the box plot for the men, it's shifted slightly to the left of that of the women.  So we could conclude that the mean pulse rate and the mean that you see here is this middle bar here in the box --- definitely lower for the men than for the women.  The width of the box plot --- so from whisker to whisker, it's about the same.  The box width is about the same.  So we could say that the variation amongst the pulse rates, it's about the same between the men and the women.

Now let's go look at our answer options and select the one that matches the observations we just made.  Answer option A says, "In general it appears the males have higher pulse rates."  No, that's not what we want.  Answer option B --- "In general it appears that males have lower pulse rates and the variation is similar."  So yeah, that's the one we want.

But before we check our answer to finalize it, let's double check the remaining answer options to make sure we've got what we want.  Answer options C says, "In general it appears males have higher pulse rates."  No, that's not right.  Answer option D says, "It appears that males have lower pulse rates than females."  That's true.  "Variation among the male pulse rates is much greater."  No, we wouldn't say that.  So we're going to stick with answer option B.  Fantastic!

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