statistics

Question

The weekly salary paid to employees of a small company that supplies? part-time laborers averages ?$850 with a standard deviation of ?$550.
?(a) If the weekly salaries are normally? distributed, estimate the fraction of employees that make more than ?$300 per week.
?(b) If every employee receives a? year-end bonus that adds ?$200 to the paycheck in the final? week, how does this change the normal model for that? week?
?(c) If every employee receives a 55?% salary increase for the next? year, how does the normal model? change?
?(d) If the lowest salary is ?$300300 and the median salary is ?$575?, does a normal model appear? appropriate?

Answer 1

use the empirical rule z=(300-850/550=-1

68 percent lie within 1 standard deviation from the mean

32% lie outside 1 sd, divide 32 by 2 = 16, 100 -16% = 84%