Statistics

There are two groups, A and B, of students in German language class. Each group consists of \( 15 \) students. In the tables, down each column, a student’s ID and grade from the mid-year’s grade report are listed. The students are evaluated according to the grading scale from \( 1 \) to \( 5 \), while \( 1 \) is the best grade and \( 5 \) is the worst one. Calculate the coefficient of variation of grades for each group and determine in which group the grades are more balanced. I.e. choose the name of the group with more balanced grades and with the correct coefficient of variation (\( \% \)) of grades. The value of the coefficient of variation is rounded to two decimal places. \[ \begin{array}{|c|c|c|c|c|c|c|c|c|}\hline \textbf{A -- students} & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\\hline \textbf{Grade} & 2 & 2 & 2 & 2 & 3 & 2 & 1 & 2 \\\hline \\\hline \textbf{A -- students} & 9 & 10 & 11 & 12 & 13 & 14 & 15 & \\\hline \textbf{Grade} & 2 & 1 & 3 & 1 &3 & 2 & 3 & \\\hline \end{array} \] \[ \begin{array}{|c|c|c|c|c|c|c|c|c|}\hline \textbf{B -- students} & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\\hline \textbf{Grade} & 2 & 1 & 1 & 2 & 2 & 3 & 1 & 2 \\\hline \\\hline \textbf{B -- students} & 9 & 10 & 11 & 12 & 13 & 14 & 15 & \\\hline \textbf{Grade} & 2 & 1 & 2 &1 &1 &1 &1 & \\\hline \end{array} \]

It is known that in the given time period one up to five pieces of the same product were sold in each of the 100 monitored shops. One piece was sold in \( 26 \) shops, \( 2 \) pieces in \( 64 \) shops, \( 3 \) pieces in \( 7 \) shops, \( 4 \) pieces in \( 2 \) shops and \( 5 \) pieces in one shop. How many pieces of the product were sold most frequently in the given shops? Choose the correct characteristic and its value.

At a weather station in Las Vegas wind speeds were measured every day at \( 7 \)pm during one month. The results are specified in the following table. \[ \begin{array}{|l|c|c|c|c|c|c|c|c|} \hline \text{Day} & 1. & 2. & 3. & 4. & 5. & 6. & 7. & 8. \\\hline \text{Wind} (\mathrm{mps}) & 3 & 2 & 1 & 1 & 2 & 2 & 1 & 3 \\\hline \\\hline \text{Day} & 9. & 10. & 11. & 12. & 13. & 14. & 15. & \\\hline \text{Wind} (\mathrm{mps}) & 2 & 1 & 2 & 2 & 4 & 2 & 4 & \\\hline \\\hline \text{Day} & 16. & 17. & 18. & 19. & 20. & 21. & 22. & 23. \\\hline \text{Wind} (\mathrm{mps}) & 4 & 2 & 2 & 3 & 2 & 12 & 13 & 6 \\\hline \\\hline \text{Day} & 24. & 25. & 26. & 27. & 28. & 29. & 30. & \\\hline \text{Wind} (\mathrm{mps}) & 5 & 7 & 2 & 3 & 8 & 9 & 12 & \\\hline\end{array} \] Determine the median of the recorded wind speeds.

You recorded the outdoor temperature in the place of your residence at the noontime during the past ten consecutive days. Now, you would like to find out the average noontime outdoor temperature in this place in the ten-day interval. What type of average do you have to use?