One-Variable Data
Find the median: 9, 11, 5, 7, 12
What is 9?
What is correlation (r)?
What is a measure of the strength and direction of a linear relationship?
Name the sampling method: Randomly choosing 10 students from each grade.
What is stratified random sampling?
A jar contains 4 red, 5 green, and 1 blue marble. A student selects one marble at random.
What is the probability the marble is green or blue?
What is 0.6?
According to CLT, what happens to shape of sampling distribution as n increases?
What is it becomes approximately normal?
Find the IQR of this data: 4, 6, 8, 10, 12, 13, 14, 15
What is 8?
What is a residual?
What is the difference between an observed y-value and a predicted y-value?
A school wants to survey student opinions on cafeteria food. They assign each student a number and use a random number generator to select 75 students to survey.
What sampling method is being used?
What is simple random sampling?
In a class, 40% of students take Spanish and 30% play a sport. If 12% of students do both, are taking Spanish and playing a sport independent events?
What is no?
In a population, 35% of people prefer online shopping. A random sample of 100 people is selected.
What is the standard deviation of the sampling distribution of the sample proportion?
What is ≈ 0.0477?
What is the IQR? What does IQR measure?
What is the interquartile range?
and measuring the spread of the middle 50% of data?
Given r = 0.9, is the linear model a good fit? Why?
What is: "Not necessarily — while r = 0.9 suggests a strong positive linear association, we need to check the scatterplot and residual plot to confirm the relationship is linear."
Explain why a double-blind design is useful in medical experiments.
What is to reduce bias from placebo effect or researcher expectations?
Expected value of rolling a fair 6-sided die?
What is 3.5?
The weights of apples in a large orchard are normally distributed with a mean of 150g and a standard deviation of 10g. If we take a random sample of 25 apples, what is the standard deviation of the sampling distribution of the sample mean?
What is 2g?
Define a skewed distribution.
What is a distribution where one tail is longer than the other?
A point has actual y = 25, predicted y = 20. What is the residual?
What is 5? (25 – 20)
How would you reduce confounding in an experiment comparing fertilizer types?
What is random assignment or using control groups and blocking?
A game costs $5 to play. A spinner gives you $10 if it lands on red (20% chance), $0 if it lands on blue (50%), and $3 if it lands on green (30%).
What is the expected value of your winnings? Should you keep playing?
What is: $2.90? Since the expected return is less than the $5 cost, it is not a good idea tokeep playing
A population of quiz scores is strongly skewed right with a mean of 80 and SD of 10. A sample of size 50 is taken.
Is the sampling distribution of the sample mean approximately normal?
What is yes, because sample size of n = 50 is large enough for the CLT to apply.
What is the relationship of outliers vs. Mean, Median and Standard deviation?
What is :"Mean and standard deviation are non-resistant to outliers, and Median is resistant"
Explain a nonlinear association.
What is a pattern in data that does not follow a straight-line trend?
A researcher wants to know the average amount of time high school students sleep each night. She surveys 50 students from her school and finds the average is 6.3 hours.
Identify the statistic and the parameter in this scenario.
What is: The statistic is 6.3 hours (sample mean from the 50 students); the parameter is the true average sleep time for all high school students.
A machine correctly labels bottles 90% of the time. In a random sample of 6 bottles, what is the probability exactly 5 are labeled correctly?
What is ≈ 0.354?
Given p̂ = 0.7, n = 50, construct a 95% confidence interval.
What is (0.57, 0.83)?