Relative and Expected Frequences (Copy)
Q1 (Non-Calculator)
A spinner is spun 50 times and lands on blue 20 times. Estimate the probability of landing on blue.
Solution:
Relative Frequency = Number of blue outcomes ÷ Total trials
Relative Frequency = 20 ÷ 50
Relative Frequency = 0.4
Answer:
0.4
Q2 (Non-Calculator)
In an experiment, a die is rolled 100 times and the number 3 appears 15 times. Estimate the probability of rolling a 3.
Solution:
Relative Frequency = 15 ÷ 100
Relative Frequency = 0.15
Answer:
0.15
Q3 (Non-Calculator)
A spinner shows relative frequency for green as 0.3. Estimate how many times green will occur in 200 spins.
Solution:
Expected Frequency = Probability × Total trials
Expected Frequency = 0.3 × 200
Expected Frequency = 60
Answer:
60
Q4 (Non-Calculator)
A biased coin is flipped 80 times and lands heads 50 times. Estimate the probability of landing tails.
Solution:
Probability of heads = 50 ÷ 80 = 0.625
Probability of tails = 1 – 0.625 = 0.375
Answer:
0.375
Q5 (Non-Calculator)
In a random draw, the probability of selecting a red ball is estimated at 0.2. If 500 balls are drawn, how many red balls are expected?
Solution:
Expected Frequency = 0.2 × 500
Expected Frequency = 100
Answer:
100
Q6 (Calculator)
A survey showed that 60 out of 150 people preferred tea over coffee. Estimate the probability that a randomly chosen person prefers tea.
Solution:
Relative Frequency = 60 ÷ 150
Relative Frequency = 0.4
Answer:
0.4
Q7 (Calculator)
In 200 throws of a biased die, the number 6 appeared 70 times. Estimate the probability of rolling a 6.
Solution:
Relative Frequency = 70 ÷ 200
Relative Frequency = 0.35
Answer:
0.35
Q8 (Calculator)
If the probability of rain tomorrow is estimated as 0.65, what is the probability that it does not rain?
Solution:
Probability of no rain = 1 – 0.65
Probability = 0.35
Answer:
0.35
Q9 (Calculator)
In a factory, the probability of a machine producing a defective item is 0.04. If 500 items are produced, how many are expected to be defective?
Solution:
Expected Frequency = 0.04 × 500
Expected Frequency = 20
Answer:
20
Q10 (Calculator)
A random survey found that the probability of a student passing an exam is 0.78. Out of 250 students, how many are expected to pass?
Solution:
Expected Frequency = 0.78 × 250
Expected Frequency = 195
Answer:
195