SOLUTION: 1. According to the IRS, for 2014, the average total itemized deductions that were taken was $25,230. This average was based on a sample of 20 individuals that took an itemized ded

Algebra ->  Probability-and-statistics -> SOLUTION: 1. According to the IRS, for 2014, the average total itemized deductions that were taken was $25,230. This average was based on a sample of 20 individuals that took an itemized ded      Log On


   

Question 1153117: 1. According to the IRS, for 2014, the average total itemized deductions that were taken was $25,230. This average was based on a sample of 20 individuals that took an itemized deduction. The standard deviation for this sample was $3,200. Assume that the data approximates a normal curve. Find a 98% confidence interval for the true population mean. please show steps with cakculator
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
the half-interval is a t df=19,0.99*s/sqrt(n)
=2.539*3200/sqrt(20)=1816.76
add and subtract from mean
($23413, $27047)
Find t by using the table or STAT TESTS 8 (T interval)
Then put in mean 0, sd sqrt(20)n-20 and .98 for CI
That is where the 2.539 comes from
then use T-interval again to get the CI.