18.11: Describing Data

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Different tables are possible

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

This is technically a bar graph, not a histogram:

$clipboard_ea99cefb4a8bc3d6c75c46cd897e990c1.png$

$clipboard_e0fcb81c339f46050406fc822de454710.png$

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

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

$(7.25+8.25+9.00+8.00+7.25+7.50+8.00+7.00) / 8=\$ 7.781$
In order, 7.50 and 8.00 are in middle positions. Median $=\$ 7.75$
$0.25 * 8=2$ $\mathrm{Q} 1$ 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: $\$ 7.00, \$ 7.375, \$ 7.75, \$ 8.125, \$ 9.00$
$0.637$

$(5 \times 0+3 \times 1+4 \times 2+2 \times 3+1 \times 5) / 15=1.4667$
Median is 8^th data value: 1 child
$0.25 \times 15=3.75 .$ 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
$clipboard_e9f1f1ea7c3ee82b36ee6da2e01e6dacf.png$

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