Types of Variables
This type of variable would describe the brand of sneakers worn by students at school.
What is a categorical variable?
A teacher asks for volunteers to stay after school to give feedback on the new lunch program. This is an example of this type of sampling.
What is voluntary response sampling?
This value is calculated by subtracting the mean from a data point and dividing by the standard deviation.
What is a z-score?
A cafeteria offers 3 different lunch options each day. What is the probability that a student randomly chooses the vegetarian option, assuming each choice is equally likely?
What is 1 out of 3 (or 1/3)?
The number of siblings a student has is this type of variable: categorical, discrete, or continuous?
What is discrete?
The number of books a student checks out from the library each month is this type of quantitative variable.
What is a discrete variable?
A principal surveys every 10th student who walks through the school doors in the morning. This is an example of this method.
What is systematic sampling?
If the mean height of 11th grade students is 66 inches with a standard deviation of 2 inches, what is the z-score of a student who is 68 inches tall?
What is 1?
Two events are considered mutually exclusive if this is true about their outcomes.
What is they cannot happen at the same time?
A school wants to survey students about homework. Instead of surveying everyone, they assign every student a number and use a random number generator to select 100 students. What sampling method is this?
What is simple random sampling?
In a survey of drivers, researchers record each person's car color, annual mileage, and age. Which of these is a continuous variable?
What is annual mileage?
A company randomly selects 5 departments and surveys all employees in each of those departments. This sampling method is called:
What is cluster sampling?
According to the Empirical Rule, about 99.7% of data falls within this many standard deviations of the mean.
What is 3 standard deviations?
In a school of 500 students, 200 play a sport, 150 are in a club, and 75 do both. What is the probability that a randomly chosen student plays a sport and is in a club?
What is 75 out of 500 (or 0.15)?
True or False: In a normal distribution, about 68% of the data falls within 1 standard deviation of the mean.
What is True?
At a local hospital, data is collected on each patient’s blood type, height, and number of emergency visits in the past year. Identify the categorical, discrete, and continuous variables.
What is: blood type (categorical), height (continuous), and number of emergency visits (discrete)?
In order to get opinions from students of all grade levels, a researcher randomly selects 10 students from each grade. This method ensures representation from each group.
What is stratified sampling?
On a standardized test, scores are normally distributed with a mean of 500 and a standard deviation of 100. A student scores a 700. This student is how many standard deviations above the mean?
What is 2 standard deviations?
At a school, students were surveyed on whether they prefer pizza or tacos, and whether they are in middle school or high school.
Middle School = 30 Pizza 20 Tacos
High School = 40 Pizza 10 Tacos
What is the probability that a student prefers pizza given they are in high school?
What is 40 out of 50 (or 0.80)?
A basketball player makes 80% of their free throws. If they shoot one free throw, what is the probability that they miss?
What is 0.20 or 20%?
A researcher studies how temperature, number of pets owned, and favorite movie genre affect stress levels. Label each variable as either categorical, discrete, or continuous.
What is: temperature (continuous), number of pets owned (discrete), favorite movie genre (categorical)?
A student only surveys their group of friends in the cafeteria for a project on school spirit. This method is easy but not representative.
What is convenience sampling?
A z-score tells you how many of these a data point is from the mean, and whether it’s above or below.
What are standard deviations?
Two events are said to be mutually exclusive if the probability of them both happening at the same time is this.
What is 0?
A data set is normally distributed with a mean of 100 and a standard deviation of 15. A student scores a 130. What is their z-score?
What is 2?