Pre-calculus

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Th weekly salaries of a sample of 100 recent graduates of a private women's college are normally distributed with a mean of \$600 and a standard deviation of \$80. Determine the interval about the sample mean that has a 1% level of confidence. Use t=2.58

Not sure if this is correct?
=600+or-2.58(80)/10
=600+or-206.4/10
=600+or-20.64

• Pre-calculus -

I am not sure what "t" is supposed to be, but the interval that the salary will be in 99% of the time is 600 + or - 206.4
206.4 happens to be 2.58 times the standard deviation.
Your t may be what other texts usually call s, the deviation from the mean divided by sigma

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