Question

In: Statistics and Probability

Question 1: Locate the Manufacturer tab. Test to determine if there is a significant difference between...

Question 1:

Locate the Manufacturer tab. Test to determine if there is a significant difference between Mean Value Added by the manufacturer and the mean Cost of Materials in manufacturing assuming a 10% level of significance.

Must complete all the parts to this problem:

  • PART 1: Use Excel to perform the Test for Equality of Variances. Copy and paste the output from Excel into a word document.
  • PART 2: Write 1 – 2 sentences on the findings from the Test for Equality of Variances. Which two-sample t-test will be needed (equal variances or unequal variances)? Support your answer by using the output from the Test for Equality of Variances. You must include: the hypotheses for the F-test, a discussion of the p-value, and the decision you reach and why.
  • PART 3: Run the test you chose in step 2 in Excel (t-test assuming equal variances or unequal variances) to test if there is a significant difference between Mean Value Added by the manufacturer and the mean Cost of Materials in manufacturing assuming a 10% level of significance. Copy and paste the output from Excel into a word document.
  • PART 4: Write 3 - 4 sentences on the findings from the Two-sample T-test. Is there a significant difference between Mean Value Added by the manufacturer and the mean Cost of Materials in manufacturing assuming a 10% level of significance? Support your answer by using the output from the test. You must include: the hypotheses for the T-test, a discussion of the p-value, and the decision you reach and why.

Data: (Table was too large so I divided each data set into two columns)

Value Added by Mfg. Cost of Materials
23518 4528 78713 3805
15724 7275 42774 7195
24506 55621 27222 57264
21667 1313 37040 1865
20712 162 12030 163
12640 1907 13674 1682
4258 53 19130 85
35210 747 33521 395
20548 328 19612 255
23442 233 5557 177
287 1717 163 943
1508 6532 314 3527
624 4850 2622 4254
2471 3509 4219 2282
4307 2176 5357 1387
673 2696 1061 1183
817 15739 707 17010
8986 999 10421 565
3145 7838 4140 5432
4076 29180 7125 45696
3806 9061 8994 6913
4276 4200 5504 11184
1239 1410 716 5735
9423 16670 8926 31892
11045 5856 11121 4696
1916 3164 2283 2790
599 3999 364 9364
2063 11750 1813 8720
34 4412 71 3527
1445 27974 1321 31527
10603 6936 12376 4909
5775 19880 9661 21531
10404 7793 19285 6232
13274 3528 18632 1689
1909 21718 2170 19273
4606 10513 7290 12954
5518 9545 8135 11858
12464 18178 12980 23474
5447 22673 4011 14343
2290 19221 5101 16515
4182 23110 3755 18543
2818 41135 2694 60857
2201 17521 3279 21819
18848 25322 20596 13897
9655 6700 10604 5523
15668 14278 24634 12657
25918 9466 28963 12578
30692 13428 8483 11065
17982 3459 6940 7621
17857 38705 8863 29591
9699 84059 2823 44486
38407 13920 29572 13398
3878 105899 3811 223639
3989 45220 1047 42367
4388 7903 2055 7760
4055 2590 1098 4363
16567 1435 11298 1674
25025 9986 34596 8120
59813 3564 27187 5476
31801 21071 19932 8760
8497 29028 9849 18028
28886 31051 46935 16787
12277 2390 11130 1020
11547 14032 13085 8114
26006 415 132880 382
3464 2761 6182 3646
2187 685 4446 506
7079 8327 7091 6604
442 2643 496 1789
1406 997
11199 8530

Solutions

Expert Solution

Test for Equal Variances:

Method

Null hypothesis All variances are equal
Alternative hypothesis At least one variance is different
Significance level α = 0.10

95% Bonferroni Confidence Intervals for Standard Deviations

Sample N StDev CI
Value Added by Mfg. 140 15340.7 (10551.0, 22667.5)
Cost of Materials 140 24569.9 (12944.6, 47394.7)

Individual confidence level = 97.5%

Tests

Method Test
Statistic
P-Value
Multiple comparisons 1.25 0.264
Levene 0.45 0.505

Since the p-value (0.505) is greater than the significance level (0.10), we cannot reject the null hypothesis.

Therefore, we can conclude that all variances are equal.

Two-Sample T-Test and CI:

Method

μ₁: mean of Value Added by Mfg.
µ₂: mean of Cost of Materials
Difference: μ₁ - µ₂

Equal variances are assumed for this analysis.

Descriptive Statistics

Sample N Mean StDev SE Mean
Value Added by Mfg. 140 12498 15341 1297
Cost of Materials 140 14110 24570 2077

Estimation for Difference

Difference Pooled
StDev
95% CI for
Difference
-1612 20482 (-6431, 3207)

Test

Null hypothesis H₀: μ₁ - µ₂ = 0
Alternative hypothesis H₁: μ₁ - µ₂ ≠ 0
T-Value DF P-Value
-0.66 278 0.511

Since the p-value (0.511) is greater than the significance level (0.10), we cannot reject the null hypothesis.

Therefore, we cannot conclude that there is a significant difference between Mean Value Added by the manufacturer and the mean Cost of Materials in manufacturing.


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