answer:False. The shape of the sampling distribution is approximately normal when the sample size is large (n ≥ 30) or, for some distributions, when the sample size is smaller but the distribution is not strongly skewed.

answer:d. It allows us to disregard the shape of the population when n is large.

answer:Private saving refers to the portion of income that is not used for consumption expenses, but instead, is set aside for future use. It is the savings that individuals or households make, either as a precautionary measure or for meeting future expenses or investments. Private saving is an important component of the national savings of a country, and it contributes to the growth of an economy.

answer:National saving refers to the total amount of savings generated in an economy over a particular time period, usually a year. It is the sum of private saving and government saving, and it represents the amount of resources available for investment in the economy. National saving is an important macroeconomic variable that affects economic growth and financial stability. When national saving is high, an economy has more resources available for investment in physical capital, human capital, and technological innovation, which can lead to higher productivity, output, and living standards in the long run.