Question

a stemplot of the iq test scores from 78 seventh - grade students in a rural midwestern school is provided. (b) we often read that iq scores for large populations are centered at 100. what percent of these 78 students have scores above 100? give your answer to one decimal place. percent: % stem leaf 7 24 7 79 8 8 69 9 0133 9 6778 10 0022333344 10 555666777789 11 0000111122223334444 11 55688999 12 003344 12 677888 13 02 13 6 (key: 7|2 = 72) to access the complete data set, click the link for your preferred software format: excel minitab14 - 18 minitab18+ jmp spss ti r mac - txt pc - txt csv crunchit!

Explanation:

Step1: Count scores above 100

Count the number of data - points in the stemplot with values greater than 100.
By counting the leaves for stems 10 (excluding the two 100s), 11, 12, and 13, we find there are \(8 + 14+ 10+3=35\) scores above 100.

Step2: Calculate the percentage

Use the formula for percentage: \(\text{Percentage}=\frac{\text{Number of scores above 100}}{\text{Total number of scores}}\times100\).
The total number of scores is \(n = 78\). So the percentage is \(\frac{35}{78}\times100\).
\[

$$\begin{align*} \frac{35}{78}\times100&=\frac{3500}{78}\\ &\approx44.9 \end{align*}$$

\]

Answer:

44.9