7th grade statistics and probability

Question 1

A bag has 8 red, 4 blue and 1 green marbles. One is picked at random. What is the probability it is red? Give a fraction in simplest form.

Answer (as a fraction)

Question 2

A survey is planned by asking only the members of the football team about favourite sports. Is this likely to give a fair (unbiased) sample?

• A. Yes
• B. No, it is biased

Question 3

Two fair dice are rolled and the scores added. What is the probability the total is 12? Give a fraction in simplest form.

Answer (as a fraction)

Question 4

You want to find out how much time students spend on sport. Which sampling method is the fairest (least biased)?

• A. Ask only your friends
• B. Pick 50 names at random from the whole school list
• C. Ask the football team
• D. Ask people leaving the gym

Question 5

To find how much students read, a teacher asks only the book club. Is this sample likely to be biased?

• A. Yes, biased
• B. No, fair

Question 6

6 friends line up for a photo. In how many different orders can they stand?

Answer 

Question 7

The probability of winning a game is 4/10. What is the probability of not winning? Give a fraction in simplest form.

Answer (as a fraction)

Question 8

A café offers 6 wraps, 5 drinks and 2 fruit pots. A meal deal is one of each. How many different meal deals are there?

Answer 

Question 9

In a survey of 45 people, 12 chose Fish. What angle does Fish get on a pie chart, in degrees?

Answer 

Question 10

Spinner A has 6 equal sections, 5 of them green. Spinner B has 6 equal sections, 3 of them green. Both are spun. What is the probability that both land on green?

Answer (as a fraction)

Question 11

Priya has 2 T-shirts, 4 pairs of trousers and 2 pairs of trainers. How many different outfits (one of each) can Priya make?

Answer 

Question 12

The probability that it rains tomorrow is 0.76. What is the probability that it does NOT rain?

Answer 

Question 13

Minutes of daily reading. Hiro's group: 16, 20, 22, 18, 17, 11, 24. Ravi's group: 23, 27, 28, 25, 25, 20, 33. Using medians, which group typically reads for longer?

• A. Hiro's group
• B. Ravi's group
• C. They are the same

Question 14

The probability of an event is 1/6. The experiment is done 168 times. How many times would you expect the event to happen?

Answer 

Question 15

A locker code has 4 digits (0–9). Repeats are allowed. How many different codes are possible?

Answer 

Question 16

Class A's mean height is 151 cm and Class B's is 163 cm. Both have a mean absolute deviation of 3 cm. The difference in means is how many MADs?

Answer