15.执行如图的程序框图,若输入的x的值为1,则输出的y的值是( )

| A. | 4 | B. | 13 | C. | 16 | D. | 28 |
7.某产品的广告费支出x与销售额y(单位:百万元)之间有如表对应数据:
(1)画出散点图;
(2)求线性回归方程;
(3)预测当广告费支出7(百万元)时的销售额.
b=$\frac{\sum_{i=1}^{n}{x}_{i}{y}_{i}-n\overline{x}g\overline{y}}{\sum_{i=1}^{n}{{x}_{i}}^{2}-{{n}_{x}}^{-2}}$,a=$\overline{y}$-b$\overline{x}$.
| x | 2 | 4 | 5 | 6 | 8 |
| y | 30 | 40 | 60 | 50 | 70 |
(2)求线性回归方程;
(3)预测当广告费支出7(百万元)时的销售额.
b=$\frac{\sum_{i=1}^{n}{x}_{i}{y}_{i}-n\overline{x}g\overline{y}}{\sum_{i=1}^{n}{{x}_{i}}^{2}-{{n}_{x}}^{-2}}$,a=$\overline{y}$-b$\overline{x}$.
6.若等比数列{an}满足anan+1=16n,则公比为( )
0 234209 234217 234223 234227 234233 234235 234239 234245 234247 234253 234259 234263 234265 234269 234275 234277 234283 234287 234289 234293 234295 234299 234301 234303 234304 234305 234307 234308 234309 234311 234313 234317 234319 234323 234325 234329 234335 234337 234343 234347 234349 234353 234359 234365 234367 234373 234377 234379 234385 234389 234395 234403 266669
| A. | -4 | B. | 4 | C. | ±4 | D. | 16 |