In a survey sample of 83 respondents, the mean number of hours worked per week is 39.04, with a standard deviation of 11.51. calculate a 95 percent confidence interval for these data, and interpret your result.

We are 95% confidence that the respondents  are worked between 36.57 hours and 41.51 hours.

Explanation:

Since we have given that

Number of respondents in a survey sample = 83

Mean number of hours worked per week = 39.04

Standard deviation = 11.51

Now, we'll calculate standard error of mean is given by

95% of confidence interval is given by

Hence, we are 95% confidence that the respondents  are worked between 36.57 hours and 41.51 hours.

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.