Blood nicotine levels in regular cigarette smokers have a mean of 100 mg but standard deviation is unknown. A smoking researcher investigates whether e-cigarettes have positive or negative effect on blood nicotine levels. He gave e-cigarettes to a random sample of 30 smokers and found a mean nicotine level of 140 mg with a standard deviation of 20 mg. Test the hypothesis that e-cigarettes had an effect. Please show all the steps involved in a hypothesis testing including proper statistical symbols, formula used, and report/interpret results in complete sentences.