About 3000 Stars Are Visible to the Unaided Eye on a Clear

question 5

Multiple Choice

About 3000 stars are visible to the unaided eye on a clear night,and the majority of these are giants and supergiants.However,our theories predict the most numerous stars should be red dwarfs.Do we have an explanation for this discrepancy? If so,what is it?

• A) Our location in the galactic plane is particularly rich in gas and dust, so an unusually large number of giants and supergiants formed here.
• B) Early in the history of our Galaxy, a shock wave passed through our part of the spiral arm, creating a large number of stars all at one time. These stars are now mostly in their giant phases.
• C) This is an example of a selection effect. The bright giants and supergiants are the most likely to be seen, even though they are not in the majority numerically.
• D) We do not have an explanation for this discrepancy.

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Definitions:

Prediction Interval

A range of values that is likely to include the value of an unknown parameter for a future observation with a specified probability.

Heteroscedasticity

A condition in regression analysis where the variance of errors or the variability of a dependent variable is unequal across all levels of an independent variable.

Residuals

The differences between observed values and the values predicted by a model, indicating the error in predictions.

Predicted Values

The expected values calculated from a regression or other predictive models based on specific input variables.