Using Excel for any calculations.

Questions 1. (10 POINTS) Emissions of nitrogen oxides, which are the major constituents of smog, can be modeled using a normal distribution. Let x denote the amount of this pollutant emitted by a randomly selected vehicle (in parts per billion, emission level). The distribution of x can be described by a normal distribution with an average emission value of 1.6 and standard deviation of 0.4. a. What percentage of vehicles have a minimum emission level of 2 ? b. Suppose that the EPA wants to offer some sort of incentive to get the worst polluters off the road. What emission levels constitute the worst 10% of the vehicles? 2. (20 POINTS) Consider sampling from a skewed population. As the sample size, n, increases, some characteristics of the sampling distribution of * change. Does an increasing sample size cause changes in the characteristics of the sampling distribution shown below? If so, specifically how does the sampling distribution change? Explain in all characteristics in a, b, c and d. a. The mean of the sampling distribution of x b. The standard deviation of the sampling distribution of X C. The shape of the sampling distribution of x d. How are the quantities, u and Me , related