Activity 27 Investigating Boomtown’s Weather How Much Rain Does Boomtown Receive??

Challenge . . . Is Boomtown’s rainfall likely to cause flooding? Key Vocabulary . . . Average Mean Median Mode Sample size

Getting Started: Read the Introduction on page 14. In your notebook, List the places that water comes from. Rain River flow from mountains Ocean waves hitting the beach Discuss in your groups . . . What is the difference between flooding and a rainfall pattern? Flooding occurs when a lot of water falls or melts in a short amount of time. A rainfall pattern is the typical amount of water an area receives from rain.

Discuss in your groups . . . What effect could flooding have on Boomtown? Increased current speed in the river Flooded streets / buildings Saturated soil Soil washed away

Calculating Mean, Median and Mode

Practice:

Discuss this with your partner. Try to answer both questions. Even though their averages are the same, Student B usually jumps farther than Student A. Student B’s median and mode jumps are longer than Student A’s longest jump. What could explain the one jump that is so different from the others? Scientists sometimes discard this type of data is there is a reasonable explanation for why it doesn’t fit.

The meet: How confident are you that Student B will win the meet? At the meet, here were the results: Student A jumped 3.5, 3.6, and 3.9 Student B jumped 3.8, 4.3 and 4.1 What does this do to their statistics? Who do you think is likely to do better in the next meet? Is your confidence increasing or decreasing?

Sample Size It is hard to determine a meaningful average based on just a few data points As you collect more data, you are more likely to obtain representative results. Sample size is the number of data in a sample

Procedure Read steps #1-6 on pages 15 and 16. You must find the mean, median and mode for centimeters for Table 1 (page 15) and Table 2 (page 16). Your GRAPHS should plot only the centimeters data.

Analysis Questions (Page 16) Answer questions 1, 2 and 4 with your group. Write your answers in your notebook.

Analysis Answers 1. Boomtown’s annual rainfall is usually between abut 72 and 99 cm. However, in 2011, it was unusually low, at 72 cm. The monthly average rainfall FLUCTUATES much more. It is as low as 0 cm in some months, and as much as 25 cm during the peak rainfall in November. There is a clear rainy season in late fall and winter; and a dry season in the late spring and summer

2a. The annual rainfall is fairly consistent from year to year with a mean of 90 cm/year, a mode of 94 cm/year, and a median of 92 cm/year. This is not a lot of rainfall overall. 2b. The rainfall is not evenly distributed throughout the year. The mean is 7.5 cm / month, but the mode is only 3 cm/month. Although most months get only 3 cm of rain, and there is not rain in June and July, November gets an average of 25 cm. This has a significant effect in raising the mean.

Analysis Answers Again (Awesome Alliteration!) 4. A. Each location is a possibility . . . Hills may have landslides or mudslides during heavy rain . The wetlands could flood during heavy rain. Parts of the cliff could be washed away during heavy rain. B. Each location is a possibility. However, the Delta Marsh is likely to be the most affected by a flood since the marsh is at the lowest elevation and the river runs directly through it.