Question

Health insurers are beginning to offer telemedicine services online that replace the common office visit. Wellpoint provides a video service that allows subscribers to connect with a physician online and receive prescribed treatments. Wellpoint claims that users of its LiveHealth Online service saved a significant amount of money on a typical visit. The data shown below ($), for a sample of 20 online doctor visits, are consistent with the savings per visit reported by Wellpoint.

93	33	40
107	82	55
55	48	40
76	49	96
94	74	71
79	95	99
53	80

Assuming the population is roughly symmetric, construct a 95% confidence interval for the mean savings for a televisit to the doctor as opposed to an office visit (to 2 decimals).

95% confidence interval: $ to $ per visit

Answer 1

Z value for a 95% confidence interval = 1.96 (using z table for normal distribution)
So confidence interval X = mean +/- Z * standard deviation = 69.47 +/- 1.96 * 22.77205 = 69.47 +/- 44.63
values taken from following table

No of doctor visits	A	Mean using AVERAGE function in excel = AVERAGE(A1:A20)	Standard Deviation using excel function = STDEV.S(A1:A20)
1	93	69.47	22.77205
2	107
3	55
4	76
5	94
6	79
7	53
8	33
9	82
10	48
11	49
12	74
13	95
14	80
15	40
16	55
17	40
18	96
19	71
20	99

Best of Luck. God Bless