few_shots: Example:
Problem/activity:
For each pair of numbers, determine if the values are equivalent. Explain your reasoning for each one.
a.
$$-0.25$$
and
$$\frac{1}{-4}$$
b.
$$-\left ( \frac{1}{4} \right )$$
and
$$\frac{-1}{-4}$$
c.
$$\frac{-1}{4}$$
and
$$-\frac{1}{4}$$


Standard options: 
A. Solve real-world and mathematical problems involving the four operations with rational numbers. (Computations with rational numbers extend the rules for manipulating fractions to complex fractions.)
B. Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers.
C. Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.


Your response:
Thought: This problem involves understanding fractions and division to divide rational numbers, such as 1, -4, 4, and -1. This problem also involves an understanding of multiplication: if p and q are integers, then -(p/q) = (-p)/q = p/(-q).
Answer: B

Now, assign the following problem or activity to one or more relevant standards it aligns with.
shot_info: fl_problem_001097

7
options: Use data from a sample survey to estimate a population mean or proportion; develop a margin of error through the use of simulation models for random sampling.

Use data from a randomized experiment to compare two treatments; use simulations to decide if differences between parameters are significant.

Evaluate reports based on data.

Recognize the purposes of and differences among sample surveys, experiments, and observational studies; explain how randomization relates to each.
problem_activity: Warm-up
In this warm-up, students use their understanding of normal distributions to determine whether the difference is likely due to the random groupings or the treatment.
Student Facing
A scientist divides 30 strawberry plants into two groups at random. One group of 15 plants will represent the control group and is grown in standard greenhouse conditions. The second group of 15 plans will represent the treatment group and will grow under the same conditions except they are grown in a different type of soil. After 6 weeks, the total weight (in grams) of the strawberries are measured for each plant. The scientist then performs a randomized experiment to compare the groups.
The data are summarized by these statistics and histogram.
Mean for the control group: 238.67 grams
Mean for the group with different soil: 347.47 grams
Mean of differences in means from randomized groupings: -0.540 grams
Standard deviation of differences in means from randomized groupings: 29.83 grams
[IMG]
Is there evidence that the difference in means from the original groupings is due to the different soil or is it likely that the difference is due to the way the plants were grouped? Explain your reasoning.
Student Response
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Activity Synthesis
The purpose of the discussion is to recall how the mean and standard deviation determine a normal distribution which can then be used to determine whether the observed difference in means is likely due to the random groupings or whether there is evidence that it is due to the treatment.
Ask students,
"Why is it useful to know the standard deviation for the differences in means from randomized groupings?" (This number gives a sense of how spread out we expect the differences to get based on the groupings. It can be used to determine a normal distribution to determine how likely it is that the observed difference in means is due to chance groupings.)
"How could the 'mean of differences in means from randomized groupings' be calculated using the original data?" (Redistribute the original data into two groups using a chance process to create new randomized groupings. Find the mean of each group and record the difference in means. Repeat the process many times to collect many differences in means for the groups. Find the mean of those recorded differences.)


correct_option_index: 1