Statistics

Two years ago, a family business reported gross profit of $3.5$ million euros. During the pandemic, the company got into trouble so that its last year gross profit fell by $20\mathrm{\%}$ and its gross profit of this year was $1$ million euros lower than of the last year. What was the average annual decrease in the gross profit reported by the company during the priod under review? Round the result to the tenth of a percent.

Four seamstresses sew doll dresses in a sheltered workshop. During the six-hour working hours, the first seamstress sewed $4$ dresses, the second $5$, the third $7$ and the fourth $4$ dresses. What was the average time needed to sew one dress on this day?

Andrea took part in a children's cycling race. The first part of the route led from the Lower Square to the Upper Square and Andrea completed it with an average speed of $10\mathrm{km}/\mathrm{h}$. Returning from the Upper Square to the Lower Square she rode the same route with an average speed of $13\mathrm{km}/\mathrm{h}$. We are interested in her average speed during the whole race. What type of average do we need to use?

In February 2021, Aneta recorded an outdoor temperature in Ostrava-Poruba, always measured at $2$ p.m. The results in ${}^{\circ }\mathrm{C}$ are shown in the following table: $$\begin{array}{|lcccccccc|}\hline \text{Day}& 1.& 2.& 3.& 4.& 5.& 6.& 7.& 8.\\ \text{Temperature }{(}^{\circ }\mathrm{C})& -1& 3& 7& 8& 3& 0& -4& -5\\ \\ \text{Day}& 9.& 10.& 11.& 12.& 13.& 14.& 15.& 16.\\ \text{Temperature }{(}^{\circ }\mathrm{C})& -4& -3& -6& -4& -3& 2& -2& 0\\ \\ \text{Day}& 17.& 18.& 19.& 20.& 21.& 22.& 23.& 24.\\ \text{Temperature }{(}^{\circ }\mathrm{C})& 3& 8& 4& 5& 5& 8& 5& 16\\ \\ \text{Day}& 25.& 26.& 27.& 28.& & & & \\ \text{Temperature }{(}^{\circ }\mathrm{C})& 15& 15& 6& 8& & & & \\ \hline\end{array}$$ Determine the mode of the recorded temperatures.