In: Statistics and Probability
A supermarket chain analyzed data on sales of a particular brand of snack cracker
at 104 stores for a certain one week period. The analyst decided to build a regresion model to predict the sales of the snack cracker based on the total sales of all brands in the snack cracker category.
a. Develop a linear regression model that helps predict
the cracker sales. Show the
prediction equation.
b. Is there sufficient evidence at 2.5% significance
level to claim that linear
relationship exists between category sales and cracker sales? Show
the
test, and make the conclusion.
c. The difference in category sales between two stores
is 150. What is the
predicted differnece of the cracker sales between these
stores?
d. Make a prediction for sales in a week where sales in
the entire snack
cracker category is 1005.
f. Produce a 90% confidence prediction interval for the
sales of the cracker
in a store where the category sales is 1005. Also produce the90
%
confidence prediction interval in a store where category sales is
900.
Can you with 90% confidence claim which store has higher cracker
sales?
CategorySales | Sales |
1348 | 394 |
1110 | 388 |
1096 | 357 |
1208 | 385 |
1063 | 346 |
1097 | 326 |
1277 | 358 |
1275 | 359 |
1328 | 360 |
1281 | 374 |
1127 | 362 |
1339 | 406 |
1055 | 354 |
1263 | 368 |
1158 | 391 |
1286 | 370 |
1401 | 372 |
1085 | 381 |
1178 | 371 |
1248 | 353 |
1241 | 372 |
1320 | 375 |
1353 | 369 |
1173 | 353 |
1208 | 364 |
1280 | 371 |
1214 | 391 |
1213 | 381 |
1291 | 371 |
1230 | 335 |
1095 | 338 |
1149 | 320 |
1305 | 370 |
1134 | 351 |
1127 | 328 |
1053 | 295 |
1107 | 318 |
1054 | 296 |
1141 | 327 |
1190 | 313 |
1071 | 346 |
1147 | 361 |
1127 | 350 |
1204 | 367 |
1301 | 411 |
1184 | 390 |
1214 | 367 |
1132 | 341 |
1213 | 380 |
1173 | 347 |
1226 | 365 |
1261 | 352 |
1118 | 341 |
1096 | 321 |
1211 | 329 |
1033 | 336 |
1228 | 361 |
1241 | 386 |
1381 | 408 |
1332 | 359 |
1253 | 375 |
1043 | 330 |
1456 | 341 |
1099 | 340 |
1044 | 336 |
1230 | 341 |
1143 | 371 |
1238 | 378 |
1357 | 371 |
1150 | 378 |
1218 | 386 |
1215 | 357 |
1238 | 376 |
1196 | 349 |
1193 | 364 |
1282 | 361 |
1317 | 365 |
1157 | 346 |
1294 | 356 |
1198 | 343 |
1436 | 358 |
1278 | 368 |
1124 | 312 |
1116 | 315 |
1109 | 338 |
1285 | 327 |
1189 | 309 |
1197 | 330 |
1091 | 345 |
1251 | 344 |
1124 | 355 |
1130 | 346 |
1067 | 328 |
1150 | 352 |
1238 | 375 |
1409 | 370 |
1264 | 377 |
1151 | 340 |
1206 | 350 |
1297 | 375 |
1164 | 364 |
1108 | 370 |
1187 | 365 |
1459 | 396 |