SAT II Math II : Other Data Analyses

Study concepts, example questions & explanations for SAT II Math II

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Example Questions

Example Question #1 : Other Data Analyses

Histogram

Refer to the above diagram. Maureen achieved a score of 603, which was the lowest score in the 601-700 range. Which of the following comes closest to being her percentile score?

Possible Answers:

\(\displaystyle 32\)

\(\displaystyle 67\)

\(\displaystyle 92\)

\(\displaystyle 21\)

\(\displaystyle 78\)

Correct answer:

\(\displaystyle 78\)

Explanation:

The histogram represents a total of 

\(\displaystyle 6 + 18 + 30 + 40 + 16 + 10 = 120\) scores.

Maureen's percentile is the percent of the scores that she outscored. Those scores were exactly the ones in the first four intervals shown - that is, 

\(\displaystyle 6 + 18 + 30 + 40 = 94\) out of the 120 scores, which was

\(\displaystyle \frac{94}{120} \times 100 \% = 78.3 \%\) of the scores. 

Percentile is given in whole numbers, so round this to 78.

Example Question #32 : Data Analysis And Statistics

Box_and_whisker_plot

The distribution of scores for a test given to a large group of students is represented by the above box-and-whisker plot.

Which of the following questions cannot be answered from the diagram without looking for other information?

Possible Answers:

What is the interquartile range of the test scores?

What is the median of the test scores?

What is the midrange of the test scores?

What is the mean of the test scores?

What is the range of the test scores?

Correct answer:

What is the mean of the test scores?

Explanation:

The midrange of the scores is the mean of the least and greatest scores, which are represented by the "whiskers" at either end:

\(\displaystyle \frac{23+94}{2} = \frac{117}{2} = 58.5\)

 

The range of the scores is the difference of the least and greatest scores:

\(\displaystyle 94-23 = 71\)

 

The median of the scores is represented by the vertical line within the box - 

\(\displaystyle M = 64\)

 

The interquartile range is the difference of the third and first quartiles, which are represented by the ends of the box:

\(\displaystyle 78-42 = 36\)

 

Note that these scores all depend on the positions of the scores. The mean, however, depends on the scores themselves, which are not reflected in the diagram. The question cannot be answered from the box-and-whisker plot.

Example Question #2 : Other Data Analyses

Histogram

Refer to the above diagram. Which of the following scores could possibly be at the eightieth percentile?

Possible Answers:

\(\displaystyle 320\)

\(\displaystyle 720\)

\(\displaystyle 420\)

\(\displaystyle 620\)

\(\displaystyle 520\)

Correct answer:

\(\displaystyle 620\)

Explanation:

The histogram represents a total of 

\(\displaystyle 6 + 18 + 30 + 40 + 16 + 10 = 120\) scores.

\(\displaystyle P_{80}\), the 80th percentile, is the score that ranks above 80% of the scores, which, here, is

\(\displaystyle 120 \cdot 0.80 = 96\) scores.

This score would outrank the 

\(\displaystyle 6 + 18 + 30 + 40 = 94\) 

scores in the first four ranges graphed, but not all of the 

\(\displaystyle 6 + 18 + 30 + 40 + 16 = 110\)

scores in the first five ranges. 

This score must fall in the fifth range shown, which is the 601-700 range.

Therefore, the correct choice of the ones given is 620.

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