Questions: Listed below are amounts of strontium-90 (in millibecquerels, or mBq) in a simple random sample of baby teeth obtained from residents in a region born after 1979. Use the given data to construct a boxplot and identify the 5-number summary. 126 127 131 135 136 138 141 144 146 147 151 151 152 153 154 161 164 164 166 171 The 5-number summary is 126, 137, 149, 157.5, and 171 all in mBq. (Use ascending order. Type integers or decimals. Do not round.) Which of the following boxplots best represents the data?

Solution Steps

First, we arrange the data in ascending order: 126, 127, 131, 135, 136, 138, 141, 144, 146, 147, 151, 151, 152, 153, 154, 161, 164, 164, 166, 171

• Minimum: 126
• Maximum: 171

Since there are 20 data points, the median is the average of the 10th and 11th values: (147 + 151)/2 = 149

The first quartile (Q1) is the median of the first 10 values. This is the average of the 5th and 6th values: (136 + 138)/2 = 137

The third quartile (Q3) is the median of the last 10 values. This is the average of the 15th and 16th values: (154 + 161)/2 = 157.5

The five-number summary is 126, 137, 149, 157.5, 171.

Now, let's analyze the provided boxplots:

• Boxplot A: This boxplot shows a minimum around 120, Q1 around 130, median around 145, Q3 around 155, and maximum around 190.
• Boxplot B: This boxplot shows a minimum around 128, Q1 around 137, median around 149, Q3 around 157, and maximum around 172.

Comparing the five-number summaries from Step 1 with the boxplots, we can see that Boxplot B closely matches the calculated five-number summary (126, 137, 149, 157.5, 171). Boxplot A does not accurately represent the data.

Final Answer