Lab Assignment 3
Packets of ground filter coffee have a nominal weight of 200g. The distribution of weights may be assumed to be normal with σ=10g. A random sample of 30 packets had the following weights.
218 207 214 189 211 206 203 217 183 186
219 213 207 214 203 204 195 197 213 212
188 221 217 184 186 216 198 211 216 200
Investigate whether there is reason to believe that the average weight of all packets is greater than 200g.
a) Write down the null and alternative hypothesis (Ho and Ha)..
b) What are the n,, σ?
c) Compute P-value based on the sample.
d) Test the hypothesis at the significance level α=0.05, i.e. reject Ho or Ha Why?
e) What conclusion can you make about the mean weight of all packets? That is, what is the plain English conclusion?
Data is repeated below for ease of pasting into Excel.
|
218 |
|
207 |
|
214 |
|
189 |
|
211 |
|
206 |
|
203 |
|
217 |
|
183 |
|
186 |
|
219 |
|
213 |
|
207 |
|
214 |
|
203 |
|
204 |
|
195 |
|
197 |
|
213 |
|
212 |
|
188 |
|
221 |
|
217 |
|
184 |
|
186 |
|
216 |
|
198 |
|
211 |
|
216 |
|
200 |