In: Statistics and Probability
Schadek Co. asked you to analyze their sales orders for the years 2018 and 2019 to see how well their sales force is working, and if they increased the sales orders or not. Use the data set in table. Sales orders of randomly selected customers (Schadek is a B2B co) are listed for 50 states.
STATE | ORDER2019 | ORDER2018 |
Alabama | 536 | 559 |
Alaska | 487 | 514 |
Arizona | 499 | 523 |
Arkansas | 554 | 562 |
California | 499 | 498 |
Colorado | 556 | 539 |
Connecticut | 513 | 509 |
Delaware | 476 | 501 |
Florida | 471 | 498 |
Georgia | 473 | 491 |
Hawaii | 469 | 486 |
Idaho | 517 | 543 |
Illinois | 591 | 576 |
Indiana | 475 | 499 |
Iowa | 575 | 593 |
Kansas | 563 | 577 |
Kentucky | 563 | 550 |
Louisiana | 546 | 564 |
Maine | 453 | 506 |
Maryland | 491 | 508 |
Massachusetts | 509 | 511 |
Michigan | 573 | 561 |
Minnesota | 577 | 580 |
Mississippi | 553 | 566 |
Missouri | 579 | 577 |
Montana | 516 | 539 |
Nebraska | 569 | 562 |
Nevada | 470 | 509 |
NewHampshire | 511 | 520 |
NewJersey | 497 | 499 |
NewMexico | 529 | 551 |
NewYork | 476 | 495 |
NorthCarolina | 474 | 493 |
NorthDakota | 561 | 592 |
Ohio | 522 | 534 |
Oklahoma | 547 | 567 |
Oregon | 499 | 526 |
Pennsylvania | 479 | 500 |
RhodeIsland | 489 | 501 |
SouthCarolina | 464 | 486 |
SouthDakota | 562 | 577 |
Tennessee | 567 | 562 |
Texas | 465 | 493 |
Utah | 545 | 575 |
Vermont | 505 | 511 |
Virginia | 495 | 510 |
Washington | 508 | 527 |
WestVirginia | 497 | 527 |
Wisconsin | 575 | 584 |
Wyoming | 551 | 547 |
1) At the 0.05 significance level, can you conclude the workforce is successful?
Here we want to test whether the sales order increase from 2018 to 2019.
Since the data is paired and sample size is n= 50> 30;
paired t - test is used.
Let Xi be the sales orders in year 2019
Similarly let Yi be the sales orders in year 2018.
Let
di = Xi - Yi
di = increase in the sales orders .
and be the average increase in the sales orders .
Hence the null hypothesis is given as
vs the alternative hypothesis will be
i.e mean sales order increase from 2018 to 2019.
Obtaining the difference di = Xi - Yi
Obtaining the mean and standard deviation of difference
= -14.14
= 210.98
Hence
The test statistic is given as
= -6.88357
Obtaining the critical value from the t-table
df = n-1
=49
level of significance
( The full table is given at the end of answer)
Decision rule:
Reject H0 if
i.e t (calculated ) > t (critical value)
Since
We failed to reject the null hypothesis.
Hence there is not sufficient evidence to conclude that mean sales order increase from 2018 to 2019.
At the 0.05 significance level the workforce is not successful ,
The t -table