Statistics (center, spread, plots) — SHSAT practice questions
On the SHSAT, Statistics (center, spread, plots) covers mean, median, range, and how a data set changes when a value is added or replaced. A student has to recover a missing score from a changed average, find a mean when two people share the same total but a different number of trials, and recompute the median after one entry is swapped. Questions are word problems about bowling, quizzes, or reports; plots, when they appear, still ask for a center or spread. Traps include treating a total as an average, forgetting to reorder before naming the middle value, and mixing mean with median. Answer choices are single numbers matching those mistakes.
Section: Mathematics 57 questions on the paper
111 practice questions in the app
Sample questions
Question 1
The average of 4 quiz scores is 84. After a fifth quiz score is included, the average becomes 86. What is the fifth quiz score?
A88
B90
C94
D96
Show answer
Answer: C — 94
The first 4 scores total 4⋅84=336. The 5 scores total 5⋅86=430. The fifth score is 430−336=94.
Question 2
The numbers of pages in 7 reports are 8,12,15,15,18,22, and 29. If the report with 29 pages is replaced by a report with 16 pages, what is the median number of pages?
A15
B16
C17
D18
Show answer
Answer: A — 15
After the replacement, the ordered data are 8,12,15,15,16,18,22. With 7 values, the median is the fourth value, which is 15.
Question 3
In a bowling league, Marcus bowled 3 games with a mean score of 150. Elena bowled 6 games. If Marcus and Elena rolled the same total pinfall, what was Elena's mean score per game?
A75
B90
C112.5
D150
Show answer
Answer: A — 75
Marcus's total pinfall is 3×150=450. Since Elena's total pinfall is also 450 but spread over 6 games, her mean score is 450÷6=75.
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