Are the 95 confidence intervals for the population mean, using t ...

[chandani]

Are the 95 confidence intervals for the population mean, using t tables and using the z table assuming that the population standard deviation is known to be 0.16, of roughly similar size? Explain.
 
  What will be an ideal response?

Question 2

How should the researcher interpret the coefficient of the dummy variable?
 
  A) Households with both adults working approximately spend 43.20 on groceries, under the assumption that all the other independent variables in the model are held constant.
  B) Households with both adults working spend, on average, 43.20 less than other households, under the assumption that all the other independent variables in the model are held constant.
  C) Households with both adults working spend, on average, 43.20 more than other households, under the assumption that all the other independent variables in the model are held constant.
  D) There is no difference between the types of households and their spending on groceries, under the assumption that all the other independent variables in the model are held constant.

[ynlevi]

Answer to Question 1

The two intervals are almost the same. The artificial (and probably incorrect) assumption that  is equal to s allows us to quote a slightly narrower interval.

Answer to Question 2

C

[chandani]

Wow, this really help

[dantucker]

Great answer, keep it coming