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Grade 7 Quiz: Data, Statistics & Probability — Easy Version 2
Grade 7 · Whoobee Name: ____________________ Date: __________
Answer every question. The lesson name before each question tells you which skill it checks — open that lesson if you need a reminder.
How to solve
This quiz mixes questions from different lessons, like a real test. Read each question carefully: the lesson name in front tells you what kind of problem it is. Check your answers, then practise the lessons where you made mistakes.
Example
Sample Spaces: Lists, Tables & Tree Diagrams: You spin a spinner with 5 equal sections and then roll a number cube. How many outcomes are in the sample space?
Answer: 30
Not quite. The answer is
💡 A random number generator gives every student the same chance of being picked. That makes the sample random. The answer is Random.
✓ Correct!
Not quite. The answer is
💡 A random number generator gives every student the same chance of being picked. That makes the sample random. The answer is Random.
💡 How to solve: Random Samples & Making Predictions
A random sample gives every member of the population the same chance of being chosen, so it represents the population well; a biased sample favors some group. To predict, use the sample as a ratio: if 12 out of 50 sampled students walk to school, then about 1250 of 600 students walk, which is 1250 × 600 = 144.
Try a similar one
To find the favorite sport of students at a school, Ana draws 40 names from a list of every student and asks them. Is the sample biased or random?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 The spinner has 4 outcomes and the coin has 2. Each spinner result can go with each of the 2, so multiply: 4 × 2 = 8. There are 8 outcomes.
✓ Correct!
Not quite. The answer is
💡 The spinner has 4 outcomes and the coin has 2. Each spinner result can go with each of the 2, so multiply: 4 × 2 = 8. There are 8 outcomes.
💡 How to solve: Sample Spaces: Lists, Tables & Tree Diagrams
The sample space is the list of every possible outcome. When one step has 2 outcomes and the next has 6, there are 2 × 6 = 12 outcomes in all — a tree diagram shows each branch. If all outcomes are equally likely, probability = (number of outcomes in the event) ÷ (number of outcomes in the sample space).
Try a similar one
You flip a coin and roll a number cube. What is the probability of getting tails and a multiple of 3?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 The bag has 6 red and 2 blue marbles, 6 + 2 = 8 in all. 2 of them are blue. P = 28. Simplify: divide the top and the bottom by 2: 28 = 14. The probability is 14.
✓ Correct!
Not quite. The answer is
💡 The bag has 6 red and 2 blue marbles, 6 + 2 = 8 in all. 2 of them are blue. P = 28. Simplify: divide the top and the bottom by 2: 28 = 14. The probability is 14.
💡 How to solve: Theoretical & Experimental Probability
Theoretical probability = favorable outcomes ÷ possible outcomes, found by reasoning (a fair number cube lands on 5 with probability 16). Experimental probability = times the event happened ÷ total trials, found from data. To predict, multiply the probability by the number of trials: 16 × 60 = 10 times.
Try a similar one
A marble is picked at random from the bag shown. What is the theoretical probability that it is blue?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Both sets have mean 10. Set A: Distance of each value from 10: 4, 3, 3, 1, 0, 1, 2, 4, 4. Mean of the distances: (4 + 3 + 3 + 1 + 0 + 1 + 2 + 4 + 4) ÷ 9 = 22 ÷ 9 = 2.44…, which rounds to 2.4. Set B: Distance of each value from 10: 1, 1, 0, 0, 0, 0, 0, 1, 1. Mean of the distances: (1 + 1 + 0 + 0 + 0 + 0 + 0 + 1 + 1) ÷ 9 = 4 ÷ 9 = 0.44…, which rounds to 0.4. 2.4 > 0.4, so A's dots are farther from the mean. The answer is A.
✓ Correct!
Not quite. The answer is
💡 Both sets have mean 10. Set A: Distance of each value from 10: 4, 3, 3, 1, 0, 1, 2, 4, 4. Mean of the distances: (4 + 3 + 3 + 1 + 0 + 1 + 2 + 4 + 4) ÷ 9 = 22 ÷ 9 = 2.44…, which rounds to 2.4. Set B: Distance of each value from 10: 1, 1, 0, 0, 0, 0, 0, 1, 1. Mean of the distances: (1 + 1 + 0 + 0 + 0 + 0 + 0 + 1 + 1) ÷ 9 = 4 ÷ 9 = 0.44…, which rounds to 0.4. 2.4 > 0.4, so A's dots are farther from the mean. The answer is A.
💡 How to solve: Comparing Data Sets: Mean & MAD
The mean is the sum of the values divided by how many there are. The mean absolute deviation (MAD) is the average distance from the mean: find how far each value is from the mean (ignore signs), add those distances, and divide by how many values there are. A bigger MAD means the data are more spread out. To compare two groups, divide the difference of the means by the MAD.
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Find the mean of the data: 8, 3, 5, 2, 5, 7.
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Count all the marbles: 4 + 1 = 5. 4 of them are red, so P(red) = 45. 45 is already in simplest form. The probability is 45.
✓ Correct!
Not quite. The answer is
💡 Count all the marbles: 4 + 1 = 5. 4 of them are red, so P(red) = 45. 45 is already in simplest form. The probability is 45.
💡 How to solve: Probability Basics
Probability = number of favorable outcomes ÷ total number of outcomes. Count the marbles of the color you want, count all the marbles, and write the answer as a fraction in simplest form.
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A bag has 3 red and 1 blue marbles. What is the probability of picking a blue marble? (as a fraction)
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 A and B are independent, so multiply their probabilities: 12 × 12. Multiply the numerators: 1 × 1 = 1. Multiply the denominators: 2 × 2 = 4. That gives 14. 14 is already in simplest form. So P(A and B) = 14.
✓ Correct!
Not quite. The answer is
💡 A and B are independent, so multiply their probabilities: 12 × 12. Multiply the numerators: 1 × 1 = 1. Multiply the denominators: 2 × 2 = 4. That gives 14. 14 is already in simplest form. So P(A and B) = 14.
💡 How to solve: Probability of Compound Events
For independent events, P(A and B) = P(A) × P(B). Multiply the numerators and multiply the denominators, then write the answer as a fraction in simplest form.
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Event A: probability = 23. Event B: probability = 14. If A and B are independent, find P(A and B).
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Mystery club members are likely to choose mystery, so the sample favors one genre. That makes the sample biased. The answer is Biased.
✓ Correct!
Not quite. The answer is
💡 Mystery club members are likely to choose mystery, so the sample favors one genre. That makes the sample biased. The answer is Biased.
💡 How to solve: Random Samples & Making Predictions
A random sample gives every member of the population the same chance of being chosen, so it represents the population well; a biased sample favors some group. To predict, use the sample as a ratio: if 12 out of 50 sampled students walk to school, then about 1250 of 600 students walk, which is 1250 × 600 = 144.
Try a similar one
To find out how students get to school, the principal asks every 10th student on an alphabetical list of all students. Is the sample biased or random?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 The spinner has 7 outcomes and the number cube has 6. Each spinner result can go with each of the 6, so multiply: 7 × 6 = 42. There are 42 outcomes.
✓ Correct!
Not quite. The answer is
💡 The spinner has 7 outcomes and the number cube has 6. Each spinner result can go with each of the 6, so multiply: 7 × 6 = 42. There are 42 outcomes.
💡 How to solve: Sample Spaces: Lists, Tables & Tree Diagrams
The sample space is the list of every possible outcome. When one step has 2 outcomes and the next has 6, there are 2 × 6 = 12 outcomes in all — a tree diagram shows each branch. If all outcomes are equally likely, probability = (number of outcomes in the event) ÷ (number of outcomes in the sample space).
Try a similar one
You spin a spinner with 4 equal sections and then flip a coin. How many outcomes are in the sample space?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 The red bar shows 13 out of 40 spins, so the experimental probability is 1340. Multiply by the number of spins: 1340 × 200 = 200 ÷ 40 × 13 = 5 × 13 = 65. Predict about 65 times.
✓ Correct!
Not quite. The answer is
💡 The red bar shows 13 out of 40 spins, so the experimental probability is 1340. Multiply by the number of spins: 1340 × 200 = 200 ÷ 40 × 13 = 5 × 13 = 65. Predict about 65 times.
💡 How to solve: Theoretical & Experimental Probability
Theoretical probability = favorable outcomes ÷ possible outcomes, found by reasoning (a fair number cube lands on 5 with probability 16). Experimental probability = times the event happened ÷ total trials, found from data. To predict, multiply the probability by the number of trials: 16 × 60 = 10 times.
Try a similar one
A marble is picked at random from the bag shown. What is the theoretical probability that it is blue?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Both sets have mean 8. Set A: Distance of each value from 8: 1, 1, 1, 1, 0, 0, 1, 1, 1, 1. Mean of the distances: (1 + 1 + 1 + 1 + 0 + 0 + 1 + 1 + 1 + 1) ÷ 10 = 8 ÷ 10 = 0.8. Set B: Distance of each value from 8: 4, 3, 2, 1, 0, 1, 1, 2, 3, 3. Mean of the distances: (4 + 3 + 2 + 1 + 0 + 1 + 1 + 2 + 3 + 3) ÷ 10 = 20 ÷ 10 = 2. 2 > 0.8, so B's dots are farther from the mean. The answer is B.
✓ Correct!
Not quite. The answer is
💡 Both sets have mean 8. Set A: Distance of each value from 8: 1, 1, 1, 1, 0, 0, 1, 1, 1, 1. Mean of the distances: (1 + 1 + 1 + 1 + 0 + 0 + 1 + 1 + 1 + 1) ÷ 10 = 8 ÷ 10 = 0.8. Set B: Distance of each value from 8: 4, 3, 2, 1, 0, 1, 1, 2, 3, 3. Mean of the distances: (4 + 3 + 2 + 1 + 0 + 1 + 1 + 2 + 3 + 3) ÷ 10 = 20 ÷ 10 = 2. 2 > 0.8, so B's dots are farther from the mean. The answer is B.
💡 How to solve: Comparing Data Sets: Mean & MAD
The mean is the sum of the values divided by how many there are. The mean absolute deviation (MAD) is the average distance from the mean: find how far each value is from the mean (ignore signs), add those distances, and divide by how many values there are. A bigger MAD means the data are more spread out. To compare two groups, divide the difference of the means by the MAD.
Try a similar one
Find the mean of the data: 6, 13, 10, 14, 7.
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
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Grade 7 Quiz: Data, Statistics & Probability — Easy Version 2
Answer every question. The lesson name before each question tells you which skill it checks — open that lesson if you need a reminder.