Question

Graduate students in a statistics department recorded hours spent consulting on 21 different projects in a particular semester:

1	1	2	2	3	5	5	8	10	15	15
18	20	20	24	30	30	30	48	50	148

Report the width of the interval. (Round your answer to two decimal places.) interval: (8.49, 37.7)

Delete the value "148" from the data set. Report the width of the new interval.' interval (9.89, 23.82)

Answer 1

a)

The width of the confidence interval id the margin of error from mean,

From the data values,

The t critical value is obtained from t distribution table for significance level = 0.05 and degree of freedom = n -1 = 21 - 1 = 20.

b)

After deleting the data point = 148 from the data set,

Now,

The t critical value is obtained from t distribution table for significance level = 0.05 and degree of freedom = n -1 = 20 - 1 = 19.