19 the stem and leaf plot shows the percentage of questions on a spanish test that were answered correctly…
19 the stem and leaf plot shows the percentage of questions on a spanish test that were answered correctly by each student in a class.\n\nspanish test\nstem | leaf\n7 | 0 0 0 5 5 5 5 5\n8 | 0 0 0 5 5 5\n9 | 0 0 5 5\n10 | 0\n\n7|0 means 70%.\n\nwhich statement is true?\na nine students answered 55% of the questions correctly.\nb half the students answered 70% or 75% of the questions correctly.\nc eight students answered more than 80% of the questions correctly.\nd ten students answered 100% of the questions correctly.
Answer
Explanation:
Step1: Count total number of students
Count the total number of leaves in the plot. $$9 + 6 + 4 + 1 = 20 \text{ students}$$
Step2: Evaluate statement A
Check the number of students who scored $55%$. The plot starts at $70%$, so $0$ students scored $55%$.
Step3: Evaluate statement B
Count students scoring $70%$ or $75%$. There are $3$ leaves of $0$ and $6$ leaves of $5$ in stem $7$. $$3 + 6 = 9 \text{ students}$$ Since $9$ is not half of $20$, this is false.
Step4: Evaluate statement C
Count students scoring more than $80%$. Count leaves in stem $8$ (excluding $0$), stem $9$, and stem $10$. $$3 \text{ (from 85)} + 4 \text{ (from 90, 95)} + 1 \text{ (from 100)} = 8 \text{ students}$$
Step5: Evaluate statement D
Check the number of students who scored $100%$. There is only one leaf in stem $10$. $$1 \text{ student scored } 100%$$
Answer:
C. Eight students answered more than 80% of the questions correctly.