7th grade statistics and probability

Question 1

Isla has 5 T-shirts, 2 pairs of trousers and 3 pairs of trainers. How many different outfits (one of each) can Isla make?

Answer 

Question 2

A locker code has 3 letters (A–Z). Repeats are allowed. How many different codes are possible?

Answer 

Question 3

A bag has 6 red, 2 green and 5 blue marbles. One is picked at random. What is P(not red)? Give a fraction in simplest form.

Answer (as a fraction)

Question 4

The probability of an event is 1/4. The experiment is done 84 times. How many times would you expect the event to happen?

Answer 

Question 5

Ava flips a drawing pin 20 times. It lands point up 14 times. What is the relative frequency of landing point up? Give a fraction in simplest form.

Answer (as a fraction)

Question 6

Which of these could NOT be a probability?

• A. 0
• B. 1
• C. 110%
• D. 0.75

Question 7

In a survey of 120 people, 20 chose Mango. What angle does Mango get on a pie chart, in degrees?

Answer 

Question 8

You want to find out which school lunch is most popular. Which sampling method is the fairest (least biased)?

• A. Ask every 10th student on the register, across all years
• B. Ask the first 10 students in the vegetarian queue
• C. Ask only Year 7
• D. Ask the kitchen staff

Question 9

A survey is planned by picking names out of a hat containing every student's name. Is this likely to give a fair (unbiased) sample?

• A. Yes
• B. No, it is biased

Question 10

A fair coin is flipped and a fair die is rolled. What is the probability of getting tails and a number greater than 4?

Answer (as a fraction)

Question 11

In a random sample of 40 students, 18 prefer online games to board games. Predict how many of the school's 600 students prefer online games to board games.

Answer 

Question 12

A die is rolled 300 times and lands on 4 exactly 56 times. How many 4s would you expect from a fair die? How many more or fewer did you get? Give (actual − expected).

Answer 

Question 13

A drawing pin is dropped 50 times. It lands point up 10 times. What is the experimental probability of landing point up? Give a fraction in simplest form.

Answer (as a fraction)

Question 14

To check a factory's light bulbs, an inspector tests every 50th bulb made during the day. Is this sample likely to be biased?

• A. Yes, biased
• B. No, fair

Question 15

The probability that it rains tomorrow is 55%. What is the probability it does NOT rain, as a percentage?

Answer 

Question 16

What is the probability of picking a vowel from the letters of the word MATHS? Give a fraction in simplest form.

Answer (as a fraction)