It is rare that you will find a gas station these days that onlysells gas. It has become more common to find a convenient storethat also sells gas. The data named “Convenient Shoppingdata†the sales over time at a franchise outlet of themajor US oil company. Each row summarize sales for one day. Thisparticular station sells gas and has a convenient store and carawash. The column labeled Sales gives thedollar sales of the convenient store and the columnVolume gives the number of gallons of gassold.
| Sales (Dollars) | Volume (Gallons) |
| 1756 | 2933 |
| 2203 | 3329 |
| 1848 | 3043 |
| 2016 | 3043 |
| 2346 | 3450 |
| 2410 | 3478 |
| 2050 | 3347 |
| 2097 | 3708 |
| 2311 | 3467 |
| 2419 | 4114 |
| 2523 | 3721 |
| 2061 | 3448 |
| 2247 | 3230 |
| 3479 | 3557 |
| 2135 | 3060 |
| 2102 | 3619 |
| 2536 | 3256 |
| 1227 | 1757 |
| 1966 | 2891 |
| 2219 | 3381 |
| 2226 | 2970 |
| 1969 | 3301 |
| 2044 | 3178 |
| 2360 | 3426 |
| 1907 | 3118 |
| 2156 | 3037 |
| 1816 | 3537 |
| 1897 | 3808 |
| 2051 | 3145 |
| 2079 | 3766 |
| 2328 | 2916 |
| 1841 | 3957 |
| 2104 | 3980 |
| 1973 | 3675 |
| 2089 | 3516 |
| 2266 | 4149 |
| 2327 | 3733 |
| 2032 | 3738 |
| 2137 | 4012 |
| 2186 | 4114 |
| 2369 | 3795 |
| 2087 | 3543 |
| 2273 | 3681 |
| 2113 | 3618 |
| 2181 | 4452 |
| 2776 | 4346 |
| 2652 | 4073 |
| 2250 | 4260 |
| 2548 | 4113 |
| 2678 | 3829 |
| 2878 | 4137 |
| 2220 | 4269 |
| 2303 | 3989 |
| 2718 | 4238 |
| 2317 | 3658 |
| 2338 | 4005 |
| 2143 | 3996 |
| 2402 | 4077 |
| 2401 | 3610 |
| 2051 | 3701 |
| 2468 | 3844 |
| 2398 | 3904 |
| 2106 | 3879 |
| 2461 | 3266 |
| 2466 | 3513 |
| 2745 | 4052 |
| 1994 | 4052 |
| 2020 | 2874 |
| 2241 | 3526 |
| 2648 | 3487 |
| 2022 | 3499 |
| 2524 | 3236 |
| 1919 | 2422 |
| 2164 | 2876 |
| 2074 | 2883 |
| 2310 | 2771 |
| 2062 | 2362 |
| 1807 | 2564 |
| 1976 | 2708 |
| 2171 | 2519 |
| 1745 | 2638 |
| 2108 | 3448 |
| 2057 | 1993 |
| 1679 | 2560 |
| 2014 | 2777 |
| 2109 | 3097 |
| 2274 | 2750 |
| 2640 | 3260 |
| 1664 | 2050 |
| 1913 | 2921 |
| 2331 | 2970 |
| 1920 | 2624 |
| 2074 | 3496 |
| 2272 | 3729 |
| 1651 | 2302 |
| 1996 | 2672 |
| 2093 | 3150 |
| 1995 | 2948 |
| 2337 | 3520 |
| 2433 | 3195 |
| 1731 | 2232 |
| 2183 | 2979 |
| 1795 | 3178 |
| 1689 | 2618 |
| 2040 | 3117 |
| 2076 | 2847 |
| 1483 | 2150 |
| 930 | 1528 |
| 1674 | 2309 |
| 1934 | 2805 |
| 2011 | 2721 |
| 2172 | 2812 |
| 1612 | 2173 |
| 1780 | 2767 |
| 2116 | 2544 |
| 1937 | 2805 |
| 1866 | 2131 |
| 2099 | 3292 |
| 2082 | 2221 |
| 1788 | 2816 |
| 2004 | 2686 |
| 1868 | 3207 |
| 2038 | 2925 |
| 2596 | 3603 |
| 1700 | 2165 |
| 1815 | 3338 |
| 1917 | 3107 |
| 2143 | 2906 |
| 2420 | 3448 |
| 2486 | 3433 |
| 1812 | 2104 |
| 2463 | 3283 |
| 2222 | 3750 |
| 2324 | 3494 |
| 2219 | 3154 |
| 2505 | 3465 |
| 2047 | 2216 |
| 2231 | 3236 |
| 2067 | 3425 |
| 2293 | 3667 |
| 2152 | 3618 |
| 1366 | 2257 |
| 2210 | 3606 |
| 2029 | 3460 |
| 2742 | 2336 |
| 2161 | 3113 |
| 2223 | 3058 |
| 2186 | 2429 |
| 2306 | 3501 |
| 1933 | 3183 |
| 2485 | 3337 |
| 2817 | 3566 |
| 2491 | 3398 |
| 1896 | 2519 |
| 2382 | 3716 |
| 2552 | 3856 |
| 2094 | 3488 |
| 2447 | 3457 |
| 2440 | 3831 |
| 2041 | 2280 |
| 2261 | 2411 |
| 2114 | 3208 |
| 2866 | 3539 |
| 2752 | 3719 |
| 2502 | 4150 |
| 1786 | 2927 |
| 2157 | 3044 |
| 2025 | 3390 |
| 2327 | 3840 |
| 2502 | 3697 |
| 2552 | 4104 |
| 2017 | 3749 |
| 2019 | 3511 |
| 2302 | 3972 |
| 2419 | 3413 |
| 2921 | 3882 |
| 2273 | 3950 |
| 2183 | 3292 |
| 2428 | 3979 |
| 2489 | 4668 |
| 2037 | 3832 |
| 2324 | 3930 |
| 2591 | 3853 |
| 2362 | 4014 |
| 3001 | 4759 |
| 1801 | 2661 |
| 1744 | 4165 |
| 2428 | 4139 |
| 2409 | 3664 |
| 2819 | 3851 |
| 1897 | 2522 |
| 1536 | 1208 |
| 2475 | 3844 |
| 2484 | 3766 |
| 2117 | 3535 |
| 2488 | 3900 |
| 2553 | 3900 |
| 2251 | 3814 |
| 2435 | 3387 |
| 2446 | 4009 |
| 2063 | 1951 |
| 2582 | 3779 |
| 1663 | 2368 |
| 2302 | 3379 |
| 2248 | 3549 |
| 2712 | 3807 |
| 2307 | 4009 |
| 2576 | 3759 |
| 1978 | 2378 |
| 2116 | 4090 |
| 2292 | 3241 |
| 2373 | 3874 |
| 2444 | 4142 |
| 2578 | 3645 |
| 1953 | 2419 |
| 2151 | 3289 |
| 2901 | 3872 |
| 2514 | 4136 |
| 2078 | 3626 |
| 2492 | 4240 |
| 1897 | 2415 |
| 2072 | 3028 |
| 2538 | 3731 |
| 2422 | 3851 |
| 2415 | 3818 |
| 2969 | 4268 |
| 1775 | 2514 |
| 2082 | 3708 |
| 2121 | 3367 |
| 2471 | 3685 |
| 2467 | 3415 |
| 2671 | 4226 |
| 1876 | 2061 |
| 1976 | 3805 |
| 2156 | 3427 |
| 2339 | 3670 |
| 2258 | 3939 |
| 2776 | 3798 |
| 2084 | 2668 |
| 2346 | 3945 |
| 2320 | 3787 |
| 2539 | 3854 |
| 2393 | 3598 |
| 2629 | 3717 |
| 2044 | 2536 |
| 2018 | 401 |
| 2350 | 2361 |
| 2452 | 4005 |
| 2041 | 2391 |
| 2038 | 3129 |
| 2181 | 3874 |
| 2516 | 4072 |
| 2181 | 3603 |
| 2427 | 4173 |
| 2111 | 3993 |
| 2182 | 3153 |
| 2794 | 3812 |
1) Draw a scatter plot for Sales onVolume where Sales is dependent on Volumeof gas sold. Does there appear to be a linear pattern that relatesto these two sequences?
2) Estimate the linear regression model using excel analysistool I showed you in class. Write the linear model and interpretthe slope (b1).
3) Interpret the R2 and tell if your linear model isa good fit or not.
4) Estimate the difference in sales at the convenient store (onaverage) between a day with 3,500 gallons sold and a day with 4,000gallons sold.
5) With regard to inference statistics, formulate a hypothesistest for the slope (b1) and decide if it is statisticallysignificant or not.
6) Construct a 95% confidence interval for the slope.
