Fractions
What is 3/5 times 5/3?
1
What is the median of: 4 3 7 8 6 5 2 ?
5
What is the median of: 3 1 2 2 3 1 2 ?
2
Mary wants to know the average height of students at her school. She stays after school for basketball practice and collects data from the first 10 people she sees coming out of the gym for water. Is this a random sample? Why or why not?
No, it's not a random sample. Playing basketball is likely correlated with being taller than average.
BONUS for 200: Name one way Mary could get a truly random sample.
A die has ten sides. If the outcome of rolling the die follows a uniform probability distribution, what are the odds of rolling a 4?
1/10
What is 11/12 times 11/12?
121/144
What is the mean of: 4 3 7 8 6 5 2 ?
5
What is the mean of: 3 1 2 2 3 1 2 ?
2
Mitchell wants to know the average height of students at her high school. She waits outside while students are coming into school and asks every tenth girl how tall she is. Is this a random sample? Why or why not?
This is not a random sample. Girls tend to be shorter than boys.
BONUS for 200: Name one way Mitchell could get a truly random sample.
A die has ten sides. If the outcome of rolling the die follows a uniform probability distribution, what are the odds of rolling an even number?
1/2
What is 3/7 divided by 6/7?
1/2
What is the total variability of: 4 3 7 8 6 5 2?
12
What is the total variability of: 3 1 2 2 3 1 2 ?
4
Jake wants to know how many students in his school got an A in math. There are 500 students in his school, so he puts all their names into a hat and pulls out 50 names. Is this a random sample? Why or why not?
Yes, it is.
BONUS for 200: Name one way Jake could have gotten a non-random sample.
A die has ten sides. If the outcome of rolling the die follows a uniform probability distribution and you roll the die twice, what are the odds of rolling a 4 on the first roll and a 5 on the second roll?
1/100
What is 15/16 divided by 3/4?
5/4
What is the mean absolute deviation of:
4 3 7 8 6 5 2?
12/7
What is the mean absolute deviation of:
3 1 2 2 3 1 2 ?
4/7
Jason wants to know the average amount of sleep that employees at his company get. There are 500 people at his company, so in order to get a sample, he just collects data from the first 50 people that leave work. Is this a random sample? Why or why not?
No, it's not. It's possible that leaving work early correlates with getting more sleep.
BONUS for 200: Name one way Jason could get a truly random sample.
A die has ten sides. If the outcome of rolling the die follows a uniform probability distribution and you roll the die twice, what are the odds that you roll a 4 and a 5 in any order?
1/50
What is 12/15 divided by 4/9?
9/5
Draw a picture of the mean and the mean absolute deviation of: 4 3 7 8 6 5 2, using a number line.
It should be centered at 5 and have a range of 12/7.
Draw a picture of the mean and the mean absolute deviation of: 3 1 2 2 3 1 2, using a number line
It should be centered at 2 and have a range of 4/7.
Julie wants to know how many oranges the grocery store sells every day. What is her population, and how could she get a random sample?
Her population is the collection of all days that the grocery store is open. She could get a random sample in a number of ways.
A die has ten sides. If the outcome of rolling the die follows a uniform probability distribution and you roll the die five times, what are the odds that you roll an even number at least once?
31/32