Examlex
Using data for a large sample of cars (n = 93), a statistics student calculated a matrix of correlation coefficients for selected variables describing each car. (a) In the spaces provided, write the two-tailed critical values of the correlation coefficient for α = .05 and α = .01 respectively. Show how you derived these critical values. (b) Mark with * all correlations that are significant at α = .05, and mark with ** those that are significant at α = .01. (c) Why might you expect a negative correlation between Weight and HwyMPG? (d) Why might you expect a positive correlation between HPMax and Length? Explain your reasoning. (e) Why is the matrix empty above the diagonal?
Correlation Matrix ( cars)
MidPr = midrange price (in - average of min and max prices
CityMPG = city MPG (miles per gallon by EPA rating)
HwyMPG highway MPG
EngSize = engine size (liters)
HPMax = horsepower (maximum)
Length length (inches)
Weight = weight (pounds)
Critical value for
Critical value for .01
Solar Cells
Instruments that directly transform sunlight into electrical energy via the photovoltaic effect.
Carbon Dioxide
This substance is a transparent, unscented gas generated through the combustion of carbon and organic materials as well as through respiration, and it is a naturally occurring part of the atmosphere absorbed by plants for photosynthesis.
Solar Space Heating
The use of solar energy to heat the interior of a building, reducing the reliance on traditional heating sources.
Carbon Dioxide
A colorless, odorless gas produced by burning carbon and organic compounds and by respiration, a greenhouse gas contributing to global warming.
Q21: The null hypothesis is rejected when the
Q28: What does the fourth letter mean in
Q42: What is the .05 critical value of
Q61: In a two-tailed test for correlation at
Q76: What are the degrees of freedom for
Q78: Which estimated multiple regression contains an
Q80: What, if anything, is wrong in this
Q85: A medical researcher wondered if there
Q94: Comparison of c means in one-factor ANOVA
Q96: If SSE is near zero in a