Question 8, 11.5.14-T HW Score: 70%, 7 of 10 points E Homework: M7-Ch11 Hw Save Part 1 of 3 O Points: 0 of 1 A random sample of 20 purchases showed the amounts in the table (in $). The mean is $47.84 and the standard deviation is $20.57. 20.58 65.86 70.42 a) Construct a 95% confidence interval for the mean purchases of all customers, assuming that the assumptions and conditions for the confidence interval have been met. 42.00 46.23 11.68 ) How large is the margin of error? 42.61 47.65 33.16 c) How would the confidence interval change if you had assumed that the population standard deviation was known to be $21? 63.65 83.95 36.13 82.07 68.58 56.43 24.56 29.22 57.21 data-2_26_2022-2_... X 24.88 50.02 File Home Insert Page ! Formu Data Review View Help a) What is the confidence interval? Get Refresh Data Sort & Data Forecast Outlin Data All Types ~ Filter * Tools (Round to two decimal places as needed.) Get & Transform... | Queries & C... |Data Types A B10 X V A B C D E F G 11.6 20.58 24.56 24.88 29.22 33.16 36.13 42 42.61 46.23 11 47.65 12 50.02 13 56.4 14 57.21 15 63.65 16 65.8 17 68.58 18 70.42 19 82.07 20 83.95 21 22 23 24 25 26