Page 103 - IM_Algebra1_FL Print Sample.pdf

b. Healthy coral.
c. Unhealthy coral
d. Answers vary. Sample response: There is a possible association between coral health and the level of nitrate concentration. This is because 71% of the time that nitrate concentration was low, the coral reef was healthy, but only 19% of the time when nitrate concentration was low. Since these values are very di erent, there is probably an association.
e. Answers vary. Sample response: There does not appear to be an association between coral health and the level of silicon dioxide concentration. Since the percentages for healthy coral in each condition are very similar, there is likely no association between the variables.
2. Answers vary. Sample response: Jada’s conclusion is correct. The youngest age group preferred sneakers without laces over the other two shoe options. The middle age group preferred sneakers with laces over the other two shoe options. The oldest age group preferred shoes that are not sneakers over the other two shoe options.
3. Answers vary. Sample responses:
◦ The left-handed people surveyed seem split pretty evenly about pen or pencil preference
while right-handed people seem to overwhelmingly prefer pen. Therefore there seems to be an association between utensil preference and handedness.
◦ Among those who prefer pencil, the handedness is pretty evenly split, but there are many more right-handers who prefer pen than left-handers. Therefore there seems to be an association between utensil preference and handedness.
Activity Synthesis
The purpose of this discussion is for students to gain a better understanding of when there is an association in the data. Discuss how calculating the relative frequency for each row or each column can help one get a better sense of the data.
Here are some questions for discussion:
• “What does it mean for two categorical variables to have an association?” (It means that the variables are statistically related to each other.)
• “For the data in Jada’s survey, the same number of people preferred sneakers without laces in the two youngest age groups. Why doesn’t this matter when deciding if there is an association between age group and shoe preference?” (It does not matter because we are looking for the relative frequency. Sneakers without laces represents the most frequent condition for the youngest age group and the least frequent condition for the second youngest age group.)
It may be worth noting that silicon dioxide is the main chemical component in sand, so it should make sense that it has little impact on coral health.
36
Teacher Guide Algebra