A regional retailer would like to determine if the variation in average monthly store sales can, in part, be explained by the size of the store measured in square feet. A random sample of
21 stores was selected and the store size and average monthly sales were computed. The results are shown in the accompanying table. Complete parts a through c below. Use a
.005 significance level where needed.
Store Size (Sq. Feet),Average Monthly Sales ($)
17520,577137.00
16040,524885.00
17170,613951.00
17240,561460.00
15960,548223.00
20050,680958.00
15440,537733.00
17170,573223.00
12370,464647.00
12880,510700.00
15530,603630.00
13040,511232.00
21570,722267.00
14580,496209.00
16560,609329.00
14990,550325.00
18720,616300.00
18840,612865.00
16300,667022.00
20080,713078.00
18380,547447.00
Calculate the sample correlation coefficient between store size and average monthly sales.
The correlation coefficient is ___.
X | Y | XY | X² | Y² |
17520 | 577137 | 10111440240 | 306950400 | 333087116769 |
16040 | 524885 | 8419155400 | 257281600 | 275504263225 |
17170 | 613951 | 10541538670 | 294808900 | 376935830401 |
17240 | 561460 | 9679570400 | 297217600 | 315237331600 |
15960 | 548223 | 8749639080 | 254721600 | 300548457729 |
20050 | 680958 | 13653207900 | 402002500 | 463703797764 |
15440 | 537733 | 8302597520 | 238393600 | 289156779289 |
17170 | 573223 | 9842238910 | 294808900 | 328584607729 |
12370 | 464647 | 5747683390 | 153016900 | 215896834609 |
12880 | 510700 | 6577816000 | 165894400 | 260814490000 |
15530 | 603630 | 9374373900 | 241180900 | 364369176900 |
13040 | 511232 | 6666465280 | 170041600 | 261358157824 |
21570 | 722267 | 15579299190 | 465264900 | 521669619289 |
14580 | 496209 | 7234727220 | 212576400 | 246223371681 |
16560 | 609329 | 10090488240 | 274233600 | 371281830241 |
14990 | 550325 | 8249371750 | 224700100 | 302857605625 |
18720 | 616300 | 11537136000 | 350438400 | 379825690000 |
18840 | 612865 | 11546376600 | 354945600 | 375603508225 |
16300 | 667022 | 10872458600 | 265690000 | 444918348484 |
20080 | 713078 | 14318606240 | 403206400 | 508480234084 |
18380 | 547447 | 10062075860 | 337824400 | 299698217809 |
Ʃx = | Ʃy = | Ʃxy = | Ʃx² = | Ʃy² = |
350430 | 12242621 | 207156266390 | 5965198700 | 7235755269277 |
Sample size, n = 21
SSxx = Ʃx² - (Ʃx)²/n = 5965198700 - (350430)²/21 = 117523228.6
SSyy = Ʃy² - (Ʃy)²/n = 7235755269277 - (12242621)²/21 = 98528176437
SSxy = Ʃxy - (Ʃx)(Ʃy)/n = 207156266390 - (350430)(12242621)/21 = 2861900817
Correlation coefficient, r = SSxy/√(SSxx*SSyy)
= 2861900817.14285/√(117523228.57143*98528176436.9521) = 0.8410
Null and alternative hypothesis:
Ho: ρ = 0 ; Ha: ρ ≠ 0
Test statistic :
t = r*√(n-2)/√(1-r²) = 0.841 *√(21 - 2)/√(1 - 0.841²) = 6.7765
df = n-2 = 19
p-value = T.DIST.2T(ABS(6.7765), 19) = 0.0000
Conclusion:
p-value < α Reject the null hypothesis. There is a correlation between x and y.
A regional retailer would like to determine if the variation in average monthly store sales can,...
please calculate the regressional model, the test hypothesis,
the rejection region for the test statistic t, the test statistic
t, and the percentage of total variation
Help A regional retailer would like to determine if the variation in average monthly store sales can, in part, be explained by the size of the store measured in square foot. A random sample of 21 stores was selected and the store size and average monthly sales were computed Complete parts a through c....
A sample of 7 department store sizes (in thousands of square feet) and revenues ( in million of dollars) are found to have a linear coefficient of 0.445. Find the critical valuesfor the linear correlation coefficient, assuming a 0.05 significance level. Is there sufficient evidence to conclude that there is a linear correlation between size and revenue of department stores?
The following multiple regression is constructed to estimate monthly sales for BEL furniture Stores in Texas. SUMMARY OUTPUT Regression Statistics Multiple R 0.936584 R Square 0.953179 Adjusted R Square 0.931556 Standard Error 17.64924 Observations 27 ANOVA df SS MS F Significance F Regression 5 952538.9 190507.8 611.5904 5.39731E-22 Residual 21 6541.41 311.4957 Total 26 959080.4 Coefficients Standard Error t Stat P-value Lower 95% Intercept 18000.86 30.15023 -0.62551 0.538372 -81.56024554 Sq. Ft. 16.20 3.544437 4.570986 0.000166 8.830512669 Inventory 0.17 0.057606 3.031541...
REGRESSION ANALYSIS The owner of large chain of ice-cream stores would like to study the effect of atmospheric temperature on sales during the summer season. Temperature is the independent variable. A random sample of 21 days is selected with the results given as follows: DAILY HIGH SALES PER STORE (Y) TEMPERATURE (X) (F) DAY 48 25000 2 28000 60 3 63 28500 4 75 30500 5 80 33600 82 32500 6 7 85 36800 8 88 39000 41000 9 90...
You wish to extend your study of the monthly sales of this particular type of men’s shirt so as to be able to compare the mean sales of the item at two types of store that make up the chain, superstores and regular stores. The population standard deviation of the monthly sales of the shirt at superstores is thought to equal 65 shirts, and the population standard deviation of the monthly sales of the shirt at regular stores is thought...
A local realtor wishes to study the relationship between selling price (in $) and house size (in square feet). A sample of 10 homes is selected at random. The data is given below: PRICE HOUSESIZE 100000 1600 107000 1750 121000 1900 124000 2150 132000 2400 140000 2300 144000 2400 158000 2700 170000 3000 182000 2900 a) Find the regression equation relating Price to Square Footage. b) Calculate the correlation coefficient, accurate to three decimal places c) Test the significance of...
A power company would like to predict the monthly heating bill for a household in a specific county during the month of January. A random sample of households in the county was selected and their January heating bill recorded along with the variables shown below. Use the regresion output shown to the right to complete parts a and b. SF: the square footage of the house Age: the age of the current heating system in years Temp: the thermostat setting,...
A power company would like to predict the monthly heating bill for a household in a specific county during the month of January. A random sample of households in the county was selected and their January heating bill recorded along with the variables shown below. Use the regresion output shown to the right to complete parts a and b. SF: the square footage of the house Age: the age of the current heating system in years Temp: the thermostat setting,...
the accompanying data contains the monthly retail sales ($millions) of a large country’s women’s clothing stores for 70 months. A sample taken from this population to estimate rhe average sales in this time period is shown below. Complete parts a through d below. 3,053 2,392 2,947 2,850 3,076 2,390 3125 2,345 2,639 3,112 2,329 3,061 2,855 3,128 3,039 2,721 2,884 2,612 2,527 3,069 2,387 2,964 2,516 2,831 2,856 a. calculate the population mean. b. calculate the sample mean. c. how...
Heat Power is a utility company that would like to predict the monthly heating bill for a household in a particular region during the month of January. A random sample of 18 households in the region were selected and their January heating bill recorded. The data is shown in the table below along with the square footage of the house (SF), the age of the heating system in years (Age), and the type of heating system (Type: heat pump =...