Review: data and probability
Review: data and probability
You want to know how long a day the pupils of the grade spend in front of a screen.
Write a good survey question, and say whom it is best to ask.
The pupils of two classes were asked whether they like mathematics:
| Yes | No | Total | |
|---|---|---|---|
| 7A | 21 | 14 | 35 |
| 7B | 18 | 6 | 24 |
What part of class 7A said “yes”? Write it as a percentage.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
What part of class 7B said “yes”? Write it as a percentage.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
In which class does a larger part of the pupils like mathematics?
The heights of 25 seedlings were measured in centimetres:
| Height (cm) | 0–4 | 5–9 | 10–14 | 15–19 |
|---|---|---|---|---|
| Frequency | 3 | 9 | 8 | 5 |
What is the relative frequency of the group 5–9? Write it as a percentage.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
What part of the seedlings are 10 cm tall or more? Write it as a percentage.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
60 pupils chose a club: 18 chose sport, 12 music, 6 art, and 24 computers.
The percentages are not written on the pie chart:
What is the relative frequency of computers? Write it as a percentage.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
What is the relative frequency of sport? Write it as a decimal.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
The chart shows the number of visitors to the library in two months:
Noa says: “There were three times as many visitors in February.”
Is Noa right? Explain.
A goalkeeper saved 45 of the 180 penalties taken against him.
Estimate the probability that he saves the next penalty. Write it as a decimal.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
About how many penalties out of 40 will he save?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
The probability of winning with a scratch card is 5%.
2,000 cards were sold.
About how many of them will win?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
Maya dropped a drawing pin 6 times, and every time it landed on its back.
Maya says: “Landing on its back is a certain event.”
Is Maya right? Explain.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power