Statistics Quiz
Questions: 16 · 10 minutes
1. A neighborhood's household incomes include one extremely high value. Which measure best represents the income of a typical household without being strongly affected by that outlier?
The mean
The median
The range
The variance
2. What does a small standard deviation generally indicate?
The distribution must have a small mean
The observations tend to cluster close to the mean
Most observations are categorical rather than numerical
The sample necessarily represents the population well
3. A survey records each participant's primary mode of transportation as car, bus, bicycle, or walking. What type of variable is this?
Discrete numerical
Ordinal categorical
Nominal categorical
Continuous numerical
4. A distribution of home prices is strongly right-skewed because a few homes are extremely expensive. How will the mean typically compare with the median?
The mean will be higher than the median
The mean will be lower than the median
The mean and median must be identical
Their relationship cannot be influenced by skewness
5. A researcher surveys 200 students selected from a university's 8,000 students. In this study, what is the sample?
The 200 surveyed students
All 8,000 university students
Every university student in the country
Only the surveyed students who completed every question
6. What is the range of the data set 3, 7, 8, 12?
9
7.5
8
6
7. In the data set 2, 4, 4, 5, 7, what is the mode?
2
4.4
5
4
8. Researchers compare two teaching methods. Students are randomly assigned to use either method. What is the main purpose of random assignment?
To make the sample representative of every student population
To guarantee that both groups earn the same average score
To increase the number of measured variables
To help balance other factors between groups, supporting a causal comparison
9. Among 120 surveyed people, 50 drink tea, and 20 of those tea drinkers add milk. What is the estimated probability that a person adds milk, given that the person drinks tea?
2/5
1/5
1/6
5/12
10. A fair coin is tossed twice. What is the probability of getting two heads?
1/2
1/3
3/4
1/4
11. A study finds that people who carry umbrellas are more likely to wear raincoats. What is the most reasonable interpretation?
Carrying an umbrella causes people to buy raincoats
Wearing a raincoat prevents people from carrying umbrellas
Rainy weather may influence both behaviors
The two behaviors must be unrelated because neither causes the other
12. In a hypothesis test, what does the p-value represent?
The probability that the null hypothesis is true
Assuming the null hypothesis is true, the probability of obtaining results at least as extreme as those observed
The size or practical importance of the observed effect
The probability that the alternative hypothesis is false
13. What is the arithmetic mean of a set of numerical values?
The value that occurs most frequently
The sum of the values divided by the number of values
The middle value after the data are ordered
The difference between the largest and smallest values
14. A 95% confidence interval is calculated for a population mean using a standard repeated-sampling method. What does the 95% describe?
Exactly 95% of individual observations fall inside the calculated interval
There is a 95% chance that the sample mean lies inside the interval
Across repeated samples, about 95% of intervals constructed this way would contain the true population mean
The interval contains 95% of all possible sample means
15. What is the main statistical benefit of selecting a simple random sample from a population?
It ensures that every selected person will respond
It guarantees that the sample exactly matches every population characteristic
It eliminates ordinary sampling variability
It reduces systematic selection bias by giving each population member a known, equal chance of selection
16. An analyst wants to show the distribution of 1,000 numerical test scores grouped into score intervals. Which display is most appropriate?
A pie chart
A scatterplot
A histogram
A line graph of chronological values