Topic Review — Statistics
Review Questions
-
Calculating all four measures from large datasets Fluency
-
The ages of players in a cricket squad are:
{24, 31, 19, 28, 23, 35, 22, 29, 26, 21, 33, 27, 20, 30, 25}
Calculate the mean, median, mode, and range. -
The number of minutes students spent on homework one evening:
{45, 60, 30, 75, 45, 90, 55, 45, 70, 50, 65, 40, 80, 45, 55}
Calculate the mean, median, mode, and range.
-
The ages of players in a cricket squad are:
-
Using technology features correctly Fluency
- Write the spreadsheet formula you would use to find the range of data in cells B2 to B20.
- A student enters a dataset and gets a mean of 0.48, but all the values in the dataset are between 40 and 60. What has most likely gone wrong?
- True or false: "If =MODE() returns an error, it means the data was entered incorrectly." Explain your answer.
- A dataset has values {12, 14, 13, 15, 12, 14, 16, 13}. Before using technology, estimate the mean. Then confirm by calculating it exactly.
-
The full inquiry process Understanding
A student is investigating: "How far do Year 7 students travel to school?"
She surveys 20 students and records their travel distances (in km):
{1.2, 3.5, 0.8, 5.1, 2.4, 1.8, 4.2, 0.5, 3.1, 2.7, 1.5, 6.3, 2.0, 3.8, 1.1, 4.5, 2.9, 0.7, 3.3, 2.2}- Calculate the mean, median, and range (round mean to 1 d.p.).
- Choose an appropriate display for this data and explain why.
- Write two conclusions that directly answer the inquiry question.
- Identify one limitation of this study.
-
Interpreting and communicating results Understanding
-
Two swimming squads recorded their 50 m freestyle times (seconds):
Squad A: {32.1, 29.8, 31.4, 30.7, 33.2, 28.9, 31.9, 30.5}
Squad B: {28.3, 35.6, 27.9, 36.1, 29.4, 34.8, 28.7, 35.2}
- Calculate the mean and range for each squad.
- Which squad is faster on average? Which is more consistent?
- A graph shows that 90% of students passed an exam. The article says this "proves the exam was too easy." Explain why this conclusion may not be valid and what additional information you would need.
-
Two swimming squads recorded their 50 m freestyle times (seconds):
-
Extended problem solving Problem Solving
-
The daily maximum temperatures (°C) recorded in a town over 14 days were:
{22, 25, 19, 28, 31, 24, 27, 23, 30, 26, 18, 29, 25, 21}
- Calculate mean, median, mode, and range.
- Display this data using a stem-and-leaf plot.
- Write three conclusions about the weather during this period.
-
Design a complete statistical inquiry for the question: "Do students who participate in school sport perform better academically?"
- Write your precise statistical question.
- Describe your data collection plan.
- Name a possible confounding factor and explain how it could affect your conclusions.
- Explain why this study could show correlation but not prove causation.
-
The daily maximum temperatures (°C) recorded in a town over 14 days were:
-
Choose the correct formula: Fluency
- Write the formula to calculate the mean of a dataset.
- How do you find the median when there is an even number of values?
- What does the range measure in a dataset?
- If a dataset has two values that both appear most often, what is the mode?
-
Spreadsheet skills: Understanding
A spreadsheet has data in cells A1:A12.
- Write the formula to find the mean.
- Write the formula to find the median.
- Write the formula to find the minimum value.
- Write a formula to find the range (maximum minus minimum).
-
Critically evaluate a statistic: Understanding
A news report says: “The average Australian household income is $120,000.”
- What measure of centre is likely being used: mean or median? Why?
- Why might the mean be misleading for household income?
- Which measure would give a better picture of a “typical” household income? Why?
-
Statistical question or not? Fluency
Identify each as a statistical question (S) or not statistical (N), and explain:
- How tall is the Eiffel Tower?
- How many hours per week do Year 7 students spend on screens?
- What is the most common blood type in Australia?
- How old is Ms Dudley?
-
Full investigation: A student wants to know which sport is most popular among Year 7 students. Problem Solving
- Write a clear statistical question they could investigate.
- How would they collect the data? Describe a fair method.
- What type of graph would best display the results? Justify your answer.
- The results show: football 12, soccer 10, basketball 8, swimming 5, other 5. Write a two-sentence conclusion.