U6S Review Day 1

How would you describe the correlation of the following scatterplot? (a)  

• Strongly Positive
• Weakly Positive
• Weakly Negative
• Strongly Negative
• No Correlation
• Unknown

Answer explanation

Positive correlation= data points increase from left to right

Strong= data points close together (but not perfect)

Data was collected on the number of siblings for students in one classroom. The results are shown on the table. Select two correct representations for the data below.

• 
• 
• 
• 

Answer explanation

The number 0 should be included

Data was collected on the number of siblings for students in one classroom. The results are shown on the table. Create a box-and-whisker plot for the data on a separate paper.

Answer explanation

Step 1: enter data in list

L = [ 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 4]

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Step 2: 5-number summary

stats (L)

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Step 3: Use step 2 results

Min = 0

Q1 = 1

Q2 (median) = 1

Q3 = 2

Max = 4

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Non-Desmos strategy:

Ask me how to solve this without Desmos if you feel you might take the exam without a laptop

Data was collected for purchases of food and beverages by fans visiting a home soccer game at Banneker.

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What is the marginal frequency of people who bought no food?

(a)  

Answer explanation

Only joint frequencies are shown

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The marginal frequencies are found by adding all numbers in the "no food" row

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60 = 30 + 20 + 10

Data was collected for purchases of food and beverages by fans visiting a home soccer game at Banneker.

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Use the data from the survey to determine which of the following statements is true about people who bought no food.

• They were 10% more likely to buy soda than water

• They were 17% more likely to buy soda than water

• Not enough information to determine

Answer explanation

How many bought no food?

60 = 30 + 20 + 10

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Of the no food group, what percent bought soda? Water?

30 ÷ 60 = 0.50 = 50% soda

20 ÷ 60 = 0.33 = 33% water

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Of the no food group, find difference in percent that bought soda vs. water:

50% - 33% = 17%

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Those who bought no food were 17% more likely to buy soda than water

What is the difference in Q1 values for Team A and Team B?

(a)  

Answer explanation

The anchor chart in the room labels Q1 for you

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Q1 for Team A is 45

Q1 for Team B is 50

Difference = 50 - 45 = 5

What is the difference in Q3 values for the Mall and Online box-and-whisker plots?

(a)  

Answer explanation

The anchor chart in the room labels Q3 for you

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Q3 for Mall is 100

Q3 for Online is 60

Difference = 100 - 60 = 40

A $50 reservation fee is paid to rent a kayak at a rate of $10 per hour. What function represents the cost rent this kayak?

• y = 50x + 10

• y = 10x + 50

• y = 10(50)^x

• y = 50(10)^x

Answer explanation

Since the question does not include a percentage, we know that this is a linear relationship

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The formula for lines is:

y = mx + b

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m = slope = rate = 10

b = initial fee = 50

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y = 10x + 50

A $50 reservation fee is paid to rent a kayak at a rate of $10 per hour. This is represented by the equation y = 10x + 50. What is the meaning of slope in words?

• For every extra hour the boat is used, total rental cost increases by 10

• For every extra hour the boat is used, total rental cost increases by 50

Answer explanation

y = mx + b

y = 10x + 50

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Think about the units for the x and y variables to answer this:

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y = $ = the total cost

x = hours = the rental time

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Recall slope units are y/x

m = $/hour

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Slope is read from x to y

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An acceptable answer is:

"For every extra hour the boat is used, total rental cost increases by 10"

A $50 reservation fee is paid to rent a kayak at a rate of $10 per hour. This is represented by the equation y = 10x + 50. What is the meaning of $50 in words?

Answer explanation

y = mx + b

y = 10x + 50

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Without the rental starting the person already has to pay $50

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The $50 is a fixed costs that occurs before the rental starts