In an effort to estimate the annal income for a new graduates, data were collected from 100 new graduates over a one year period. The sample showed an average income of $68000. Assume a standard deviation $1200.

The 98% confidence interval estimate of the population mean amount earned is

a)67764.80 to 68235.20 per year

b)67803.20 to 68196.80 per year

c)47654.53 to 48345.47 per year

d)67720.40 to 68279.60 per year

e)67000.00 to 68000.00 per year

If the data were collected for a sample of 50 graduates rather than 100, the 95% confidence interval estimate of the population mean amount earned is

a)67667.38 to 68332.62 per year

b)67764.80 to 68235.20 per year

c)67654.53 to 68345.47 per year

d)67720.40 to 68279.60 per year

e)67000.00 to 69000.00 per year