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Multiple Regression: Examine the relationship between the number of units produc

ID: 3303950 • Letter: M

Question

Multiple Regression: Examine the relationship between the number of units produced and the number of production batches and their effect on total manufacturing overhead.Consider the following in your report: a. What is the coefficient of determination? How did multiple (versus single) regression help/hurt the r-squared? b. What is the estimated Variable Manufacturing Overhead Per Unit? c. What is the estimated Total Fixed Manufacturing Overhead?

Queens Lamps Inc specializes in manufacturing custom designed lamps. It is a low volume manufacturer. Its cost data for four years is as follows. Sales Price Per Unit: $ 400.00 Variable Selling and General Expenses per unit $              12.00 Monthly Fixed Selling and General Expenses $              2,000 Observation Number Month Year Number of Production Batches Units Produced Manufacturing Overhead Machine Hours Direct Material Cost Direct Labor Cost                     1 Jan 20X1                           8            121                10,991         1,557         3,703         4,646                     2 Feb 20X1                           4            103                   9,724         1,259         3,059         4,408                     3 Mar 20X1                           5               82                   9,830            970         2,411         3,674                     4 Apr 20X1                           7            123                11,006         1,631         3,653         4,723                     5 May 20X1                         10               95                10,413         1,235         2,850         4,028                     6 Jun 20X1                           5            100                10,403         1,391         2,970         4,280                     7 Jul 20X1                         11            125                11,307         1,479         3,750         5,750                     8 Aug 20X1                           5               68                   9,716            955         2,060         2,530                     9 Sep 20X1                           3            130                10,310         1,808         3,822         4,992                   10 Oct 20X1                           6               80                   9,622            988         2,448         3,520                   11 Nov 20X1                           4            124                10,237         1,483         3,683         4,613                   12 Dec 20X1                         10            128                11,120         1,597         3,802         5,530                   13 Jan 20X2                           5            121                10,311         1,715         3,630         4,453                   14 Feb 20X2                           7               71                10,103            951         2,173         3,039                   15 Mar 20X2                           7            122                10,777         1,507         3,587         4,197                   16 Apr 20X2                         10               35                   9,822            473         1,050         1,330                   17 May 20X2                           4            116                10,527         1,493         3,480         4,083                   18 Jun 20X2                           8               44                   9,331            578         1,294         2,006                   19 Jul 20X2                         11               71                10,697            886         2,087         2,698                   20 Aug 20X2                           6               57                   9,767            771         1,727         2,440                   21 Sep 20X2                         10               56                10,241            692         1,697         2,419                   22 Oct 20X2                           5               73                   9,695            940         2,146         3,066                   23 Nov 20X2                           6            128                10,746         1,498         3,802         5,171                   24 Dec 20X2                           9            114                10,790         1,615         3,420         4,697

Explanation / Answer

Here manufacturing overhead is dependent variable and number of production batches and units produced are independent variables.

This is problem of multiple regression.

Now we have to fit regression of manufacturing overhead on number of production batches and units produced.

We can do regression in EXCEL.

steps :

ENTER data into EXCEL sheet --> Data --> Data Analysis --> Regression --> ok --> Input Y Range : select range of Manufacturing overhead --> Input X range : select range of number of production batches and units produced --> Output Range : select one empty cell --> ok

Here correlation between manufacturing overhead and number of production batches and units produced is 0.9361.

There is poisitve relationship between manufacturing overhead and number of production batches and units produced.

R-sq = 0.8762

It expresses the proportion of variation in manufacturing overhead which is explained by variation in number of production batches and units produced.

The regression equation is,

manufacturing overhead= 7899.28 + 133.77*number of units produced + 15.61*units produced.

intercept= 7899.28

Regression coefficients = 133.77 and 15.61

Interpretation of slopes : When we fixed number of units produced then one unit change in units produced will be 15.61 units increase in manufacturing overhead.

When we fixed unit change then one unit change in number of units produced will be 133.77 units increase in manufacturing overhead.

Hypothesis testing :

Overall significance :

Here we have to test the hypothesis that,

H0 : Bj = 0 Vs H1 : Bj not= 0

where Bj is population slope for jth independent variable.

Assume alpha = 0.05

Here test statistic follows F-distribution.

F = 74.31

P-value = 2.98E-10

P-value < alpha

Reject H0 at 5% level of significance.

Conclusion : Atleast one of the population slope is differ than 0.

Individual significance :

Here we have to test the hypothesis that,

H0 : B = 0 Vs H1 : B not= 0

where B is population slope for an independent variable.

Assume alpha = 0.05

Here test statistic follows t-distribution.

Here we can see that all the three variables are significant since p-value for all is less than alpha.

P-value < alpha

Reject H0 at 5% level of significance.

We get significant result about t-test.

SUMMARY OUTPUT Regression Statistics Multiple R 0.936056 R Square 0.8762 Adjusted R Square 0.86441 Standard Error 199.8574 Observations 24 ANOVA df SS MS F Significance F Regression 2 5936671 2968336 74.31434 2.98E-10 Residual 21 838802.5 39942.98 Total 23 6775474 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95.0% Upper 95.0% Intercept 7899.284 204.8807 38.55554 5.62E-21 7473.212 8325.357 7473.212 8325.357 Number of Production Batches 133.7729 17.36656 7.702902 1.5E-07 97.65716 169.8886 97.65716 169.8886 Units Produced 15.6086 1.423141 10.96771 3.75E-10 12.64902 18.56819 12.64902 18.56819