Aarp reported on a study conducted to learn how long it takes individuals to prepare their federal income tax return (aarp bulletin, april 2008). the data contained in the webfile named taxreturn are consistent with the study results. these data provide the time in hours required for 40 individuals to complete their federal income tax returns. using past years' data, the population standard deviation can be assumed known with σ = 11 hours. what is the 95% confidence interval estimate of the mean time it takes an individual to complete a federal income tax return? round your answer to one decimal to hoursreturn preparation time(hours)35.330.537.426.513.049.9 28.844.061.60.540.534.947.936.624.1 39.847.818.536.639.214.537.340.549. 345.528.319.55.652.641.445.339.033. 729.414.540.133.736.95.633.7

Confidence interval: (30.1,36.9)

Step-by-step explanation:

We are given the following data set:

35.3,30.5,37.4,26.5,13.0,49.9,28.8,44.0,61.6,0.5,40.5,34.9,47.9,36.6,24.1,39.8,47.8,18.5,36.6,39.2,14.5,37.3,40.5,49.3,45.5,28.3,19.5,5.6,52.6,41.4,45.3,39.0,33.7,29.4,14.5,40.1,33.7,36.9,5.6,33.7

Formula:

where are data points, is the mean and n is the number of observations.  

(given)

n = 40

Confidence interval:

Putting the values, we get,

correct

step-by-step explanation:

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m