The distribution of annual earnings of all bank tellers with five years of experience is skewed negatively. This distribution has a mean of Birr 15,000 and a standard deviation of Birr 2,000. If we draw a random sample of 30 tellers, what is the probability that their earnings will average more than Birr 15,750 annually?
Required:
• Calculate µ and δ-x
• Calculate Z for X
• Find the area covered by the interval
• Interpret the results