Question

Mean Wait Time: Not In Program	Mean Wait Time: In Program
315	193
328	230
278	246
312	146
270	196
189	251
261	190
224	232
275	194
325	195
291	195
243	238
257	275
319	249
261	262
291	231
251	281
234	193
257	322
341	190
313	234
271	268
246	260
340	223
318	265
234	228
214	194
250	295
241	241
291	276	The owners of an ice cream shop franchise, looking to reduce wait times for customers, launched a pilot program where customers could use a smartphone app to place orders. The accompanying data set shows the mean wait times (in seconds) for in-store and drive-through customers at 30 shops participating in the pilot program and at 30 shops not in the program. Assume that the population variance of mean wait times is equal for both groups and that the mean wait times are normally distributed for both groups. Let the mean wait times of the shops not in the program be the first sample, and let the mean wait times of the shops in the program be the second sample. At the 0.10 level of significance, is there evidence that the smartphone app reduces wait times? Perform the test using Excel. Find the test statistic, rounded to two decimal places, and the p-value, rounded to three decimal places.

Answer 1

Following is the output of t test generated by excel:

The test statistics is

t = 4.10

The p-value is: 0.000

Since p-value is less than 0.10 so we reject the null hypothesis. That is we can conclude that the smartphone app reduces wait times.