Thank you for using the site. I'll be happy to help you with these problems.
Do you happen to have this information in a Word or PDF file that you could attach? Some of the tables seem to be missing some information.
At this point, the only part I need clarification of is Table 5 in Question #4. Some of the frequencies are missing from the table.
I just wanted to let you know that I haven't forgotten about this assignment. I'm sorry about the delay in replying, but I was away from my computer for a while (had to get some sleep). I'm reworking some of the problems to match the formulas that your class appears to be using. Unfortunately, a lot of this material is not standardized, so the important point is to do it the way that your course is teaching.
I'll have this posted for you as soon as I finish.
Here are my solutions:
Note that there may be slight differences due to rounding, or how the frequency distribution was set up.
Regarding that solutions that you worked out, here are some comments.
In your work for Question 1b, it seems like you haven't accounted for all of the data. There are 40 values in the data set, but you have only tallied 28 of them.
In Question 2 (page 2), there is an error in your formula for the standard deviation. In the second term under the radical sign, the "n" in the denominator should not be squared. The term should be (∑fx)^2 / n.
In Question 3, a class width of 2.4 ends up giving you 7 classes instead of the 6 that were calculated using the formula for k. In my solution, I adjusted the class width to 2.5 so that 6 classes will cover the range of data. I did this just in case your instructor is being picky about the number of classes. In the real world, your class width of 2.4, and having 7 classes instead of 6, would be fine. The difference in class width will slightly affect the calculations for the median and the quartiles.
Please feel free to ask if you have questions about any of these solutions.
You're quite welcome. I'm glad that I could help.
I really don't see any place where I could take out any parts of the solutions. If I were to remove anything, then you'd pretty much just have the final solution left with no supporting calculations.
Please let me know if I have misunderstood what you are asking for.