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Learning Math Home
Data Session 3 Solutions
Session 3 Part A Part B Part C Part D Homework
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Session 3 Materials:

A B C D 


Solutions for Session 3, Part B

See solutions for Problems: B1 | B2 | B3

Problem B1

A histogram offers a better graphical perspective on an entire data set. One disadvantage is that the actual data values cannot be determined from a histogram, only the number of values within intervals.

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Problem B2

There are many descriptive statements that could provide an answer to this question. Here are some things you may have noted:


All estimates are between 30 seconds and 100 seconds. The range is 70 seconds, which indicates a lot of variation in the estimates.


There is a concentration of estimates between 50 seconds and 70 seconds. Thirty-five of the 52 estimates (or 35 / 52 = 67.3%) fall within this interval. The range of this interval is only 20 seconds.


You may have noticed that because the histogram does not indicate individual pieces of data, we cannot look for a single number that represents the data.

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Problem B3


There are five estimates below 50 seconds and 12 estimates of 70 seconds or higher. In total, 17 of 52 estimates were outside the interval from 50 to less than 70 seconds.


Since 17 estimates were outside this interval, the remaining 35 of 52 estimates were within the interval.


There are four estimates below 40 seconds and five estimates of 80 seconds or higher. In total, nine of 52 estimates were outside this interval.


No, the answer to question (a) suggests that this group was roughly in line with the original group, since there were only 26 responses in the original group. The proportion for this group, 17 / 52 = 32.7%, is only slightly better than the proportion for the original group, which was 9 / 26 = 34.6%. Effective comparisons between groups of different sizes must be relative comparisons.

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