
18.11: Describing Data


1.

1. Different tables are possible

$$\begin{array}{|l|l|} \hline \text { Score } & \text { Frequency } \\ \hline 30 & 1 \\ \hline 40 & 0 \\ \hline 50 & 4 \\ \hline 60 & 3 \\ \hline 70 & 6 \\ \hline 80 & 5 \\ \hline 90 & 2 \\ \hline 100 & 3 \\ \hline \end{array}$$

1. This is technically a bar graph, not a histogram:

3.

1. $$5+3+4+2+1=15$$
2. $$5 / 15=0.3333=33.33 \%$$

5. Bar is at $$25 \% .25 \%$$ of $$20=5$$ students earned an $$A$$

7.

1. $$(7.25+8.25+9.00+8.00+7.25+7.50+8.00+7.00) / 8=\ 7.781$$
2. In order, 7.50 and 8.00 are in middle positions. Median $$=\ 7.75$$
3. $$0.25 * 8=2$$ $$\mathrm{Q} 1$$ is average of $$2^{\mathrm{nd}}$$ and $$3^{\mathrm{rd}}$$ data values: $$\ 7.375 \quad 0.75 * 8=6 . \mathrm{Q} 3$$ is average of $$6^{\mathrm{th}}$$ and $$7^{\mathrm{th}}$$ data values: $$\ 8.125$$ 5-number summary: $$\ 7.00, \ 7.375, \ 7.75, \ 8.125, \ 9.00$$
4. $$0.637$$

9.

1. $$(5 \times 0+3 \times 1+4 \times 2+2 \times 3+1 \times 5) / 15=1.4667$$
2. Median is 8th data value: 1 child
3. $$0.25 \times 15=3.75 .$$ Q1 is 4 $$^{\text {th}}$$ data value: 0 children $$0.75 \times 15=11.25 .$$ Q 3 is $$12^{\text {th}}$$ data value: 2 children 5 -number summary: 0,0 1,2,5

11. Kendra makes $90,000. Kelsey makes$40,000. Kendra makes \$50,000 more.

18.11: Describing Data is shared under a CC BY-SA 3.0 license and was authored, remixed, and/or curated by David Lippman via source content that was edited to conform to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.