Sheet1
Starting Weight Final Weight Weight Loss
282 282 Determine for weight loss column
280 278.5 Sample Mean:
188 179.5 Null Population Mean:
273 267 Sample Standard Deviation:
201 194 Sample Size:
180 171 Standard E
or:
308 302.5 CI Lower Limit
219 213.5 CI Upper Limit
196 193
181 180 Perform Hypothesis Test
195 187 T-Statistic:
248 244 T-critical Value(s)
276 275.5 Reject the Null Hypothesis?
213 209
204 203.5
270 270
303 293.5
263 257
294 293
277 270
191 189.5
184 175
245 242.5
198 196.5
296 287
196 194.5
296 295
239 229
286 285
232 226
190 190
218 217.5
280 272
314 304.5
227 223
285 279
191 191
188 181
298 290
296 292.5
A company wants to (cheaply) test the effects of a weight loss drug they're developing. They claim that the drug will help any person who is overweight lose 5 pounds in a week. They decide to conduct a hypothesis test at the 99% significance level to further strengthen their claim. Thus they decide to compensate a group of 40 people who are overweight to take this drug for a week and come back for a weight in.
They decided to proceed with a hypothesis test and they want to disprove the null hypothesis that their drug does not help people who are overweight with weight loss (that is, m=0)
Part A: State the null hypothesis and alternative hypotheses for this particular test.
Part B: Use the data given to determine the following statistical measures and find the confidence interval at 99% for the average weight loss in one week. Is a 5 pounds loss contained within this confidence interval? If so, does that mean that customers can expect to lose 5 pounds on this drug?
Part C: Perform a hypothesis test! Which type of tailed-test will you use? Find the t-statistic for the data and determine whether to reject the null hypothesis. Hint: the critical value of the t-distribution with 39 degrees of freedom is approximately XXXXXXXXXXIf you have two critical values, separate them with commas and list your positive value first in the T-Critical Value(s) cell.
Part D: Were you able to reject the null hypothesis at 99% significance? If so, interpret the significance of this rejection. Does it provide sufficient evidence to prove that their drug helps their customers lose 5 pounds in one week? If you think this is insufficient evidence, describe how you would change the experiment to make it more meaningful.