Nt1330 Unit 5 Study Guide

Can the frequency of cricket chirps be used to predict the outdoor temperature? According to one of the founding fathers of communications engineering, George Washington Pierce, the answer is yes. During his career, Pierce invented several pieces of technology that earned him patents and a lot of money from companies like RCA and AT&T. When he retired, Pierce built a device that allowed him to record the sounds made by various insects near his New Hampshire home. In 1948, he published his research findings in a book titled The Songs of Insects. In this Activity, you will examine data that Pierce collected on the number of chirps per second of the striped ground cricket and the outdoor temperature in degrees Fahrenheit. You will compose
a Word document with the answers to each of the numbered questions below as well as your scatterplot with regression line.
Cricket chirps per second
Outdoor temperature (F)
20.0
88.6
16.0
71.6
19.8
93.3
18.4
84.3
17.1
80.6
15.5
75.2
14.7
69.7
17.1
82.0
15.4
69.4
16.2
83.3
15.0
79.6
17.2
82.6
16.0
80.6
17.0
83.5
14.4
76.3
QUESTIONS
1.
Enter the data into your MS Excel spreadsheet. Which is the explanatory variable?
2. Make a well-labeled scatterplot of the data. Describe the direction, form, and strength of the relationship. Are there any outliers?
3. Use MS Excel to find the least-squares regression line for these data. Record the equation, paying attention to precision.
[After plotting the scatterplot, position cursor on one data point and right click. Choose Add Trendline, then select linear. Experiment with Chart Layouts to find regression equation. ]
4. Interpret the slope and the y-intercept of the least-squared line in this setting.
5. Use the equation to predict the temperature when there are 15 cricket chirps per second.
6. Determine the value of the Correlation Coefficient. [Remember that the r is the square root of r2] Comment on how well the regression line fits the data.
7. Is it reasonable to use the equation to predict the temperature when there are 25 cricket chirps per second? Explain.
8. Crickets make their chirping sounds by rapidly rubbing their wings together. From Pierce’s data, we see that outdoor temperature increases as the number of cricket chirps increases. Can we conclude that the increased number of chirps causes the temperature to increase (maybe due to the heat generated from wings rubbing together)?
Explain.