statistics question
HW11
MGMT 650 Summer 2020 Week 11 Homework Questions (Last updated 4/1/2020)
Chi Square
| Saeko has a yarn shop and wants to test her theory on what types of colors she is selling. | |||
| She believes that Black, White, the Primary Colors, and Tertiary colors sell in equal amounts. | |||
| The primary colors are blue, red, and yellow; while the tertiary colors are Brown, Green, and Purple. | |||
| Test Saeko's theory using the 5 step hypothesis testing analysis and Chi Square at the .10 level of significance. | |||
| (Optional) | Use the "Pivot Table Data" tab to create a pivot table that shows Saeko the number of yards that were sold in the various yarn types during the busiest weekend of her shop last year. | ||
| Here is the pivot table that you should have created. It is optional so that you can practice your pivot table skills. | |||
| Row Labels | Count of Color Type | Sum of Yards | |
| Black | 23 | 35856 | |
| Blue | 16 | 17053 | |
| Brown | 13 | 13426 | |
| Green | 12 | 12509 | |
| Purple | 12 | 12131 | |
| Red | 8 | 8393 | |
| White | 26 | 37666 | |
| Yellow | 12 | 12874 | |
| (blank) | |||
| Grand Total | 122 | 149908 | |
| 1) | Using the pivot table that you just created, fill in the blanks in the following table: | ||
| Primary Colors consists of the sum of Blue, Red, and Yellow yarn sold | |||
| Tertiary Colors consists of the sum of Brown, Green, and Purple Colors Sold. | |||
| The Total in this chart must equal the Grand Total, Cell D19 in the above table. | |||
| Black | |||
| White | |||
| Primary Colors | |||
| Tertiary Colors | |||
| Total | |||
| This table represents the observed data in the Chi Square analysis. | |||
| Find the Expected values for each of the colors. Saeko expects that the colors sell in equal amounts. | |||
| Color Type | Sum of Yards | ||
| Black | |||
| White | |||
| Primary Colors | |||
| Tertiary Colors | |||
| Total | |||
| Subtract the Expected values from the observed values | |||
| Color Type | Sum of Yards | ||
| Black | |||
| White | |||
| Primary Colors | |||
| Tertiary Colors | |||
| Square the values just found | |||
| Color Type | Sum of Yards | ||
| Black | |||
| White | |||
| Primary Colors | |||
| Tertiary Colors | |||
| Divide each square by the expected value and add together | |||
| Color Type | Sum of Yards | ||
| Black | |||
| White | |||
| Primary Colors | |||
| Tertiary Colors | |||
| Total | |||
| 2) | This total is your Chi Square test statistic | ||
| Use the 5 step hypothesis testing procedure to determine if Saeko's hypothesis that the colors sell in equal amounts is true. | |||
| What is the null hypothesis? | |||
| What is the alternative hypothesis? | |||
| What is the level of significance? | |||
| 3) | What is the Chi Square test statistic? | ||
| 4) | What is the Chi Square critical Value? | Use =CHISQ.INV() | |
| What is your answer to Saeko? | |||
Pivot Table Data
| Customer | Color Name | Color Type | Yards | Meters |
| 1 | Coriander | White | 1155 | 1,056.13 |
| 2 | Black | Black | 1504 | 1,375.26 |
| 3 | Daffodil | Yellow | 904 | 826.62 |
| 4 | Black | Black | 1850 | 1,691.64 |
| 5 | Opal | Blue | 1497 | 1,368.86 |
| 6 | Toffee | Brown | 929 | 849.48 |
| 7 | Ruby | Red | 918 | 839.42 |
| 8 | Ash | Blue | 584 | 534.01 |
| 9 | Black | Black | 2363 | 2,160.73 |
| 10 | Ash | Blue | 816 | 746.15 |
| 11 | Black | Black | 1685 | 1,540.76 |
| 12 | Whirlpool | Blue | 1402 | 1,281.99 |
| 13 | Verde | Green | 972 | 888.80 |
| 14 | Regal | Purple | 590 | 539.50 |
| 15 | Lynx | Brown | 1263 | 1,154.89 |
| 16 | Yellow Rose | Yellow | 791 | 723.29 |
| 17 | Chocolate | Brown | 1331 | 1,217.07 |
| 18 | Mist | White | 2425 | 2,217.42 |
| 19 | Whirlpool | Blue | 848 | 775.41 |
| 20 | Alfalfa | Green | 990 | 905.26 |
| 21 | Ruby | Red | 1269 | 1,160.37 |
| 22 | Verde | Green | 1441 | 1,317.65 |
| 23 | Sky | White | 2269 | 2,074.77 |
| 24 | Black | Black | 1496 | 1,367.94 |
| 25 | Whirlpool | Blue | 815 | 745.24 |
| 26 | Black | Black | 1570 | 1,435.61 |
| 27 | Mist | White | 1999 | 1,827.89 |
| 28 | Alfalfa | Green | 1217 | 1,112.82 |
| 29 | Jade | Green | 737 | 673.91 |
| 30 | Yellow Rose | Yellow | 1063 | 972.01 |
| 31 | Cream | White | 1799 | 1,645.01 |
| 32 | Black | Black | 2721 | 2,488.08 |
| 33 | Ruby | Red | 575 | 525.78 |
| 34 | Mist | White | 2305 | 2,107.69 |
| 35 | Yellow Rose | Yellow | 828 | 757.12 |
| 36 | Black | Black | 2037 | 1,862.63 |
| 37 | Sky | White | 2157 | 1,972.36 |
| 38 | Periwinkle | Purple | 1363 | 1,246.33 |
| 39 | Coriander | White | 2179 | 1,992.48 |
| 40 | Black | Black | 1846 | 1,687.98 |
| 41 | Yellow Rose | Yellow | 1290 | 1,179.58 |
| 42 | Black | Black | 1894 | 1,731.87 |
| 43 | Periwinkle | Purple | 973 | 889.71 |
| 44 | Black | Black | 2393 | 2,188.16 |
| 45 | Black | Black | 2476 | 2,264.05 |
| 46 | Mist | White | 2428 | 2,220.16 |
| 47 | Coriander | White | 2488 | 2,275.03 |
| 48 | Cream | White | 2379 | 2,175.36 |
| 49 | Verde | Green | 600 | 548.64 |
| 50 | Black | Black | 1720 | 1,572.77 |
| 51 | Daffodil | Yellow | 1160 | 1,060.70 |
| 52 | Chocolate | Brown | 1264 | 1,155.80 |
| 53 | Regal | Purple | 1441 | 1,317.65 |
| 54 | Daffodil | Yellow | 915 | 836.68 |
| 55 | Coriander | White | 839 | 767.18 |
| 56 | Black | Black | 1468 | 1,342.34 |
| 57 | Black | Black | 831 | 759.87 |
| 58 | Lynx | Brown | 936 | 855.88 |
| 59 | Periwinkle | Purple | 854 | 780.90 |
| 60 | Daffodil | Yellow | 1250 | 1,143.00 |
| 61 | Coriander | White | 1352 | 1,236.27 |
| 62 | Verde | Green | 1163 | 1,063.45 |
| 63 | Lynx | Brown | 1329 | 1,215.24 |
| 64 | Alfalfa | Green | 1176 | 1,075.33 |
| 65 | Cream | White | 703 | 642.82 |
| 66 | Daffodil | Yellow | 836 | 764.44 |
| 67 | Periwinkle | Purple | 1468 | 1,342.34 |
| 68 | Cream | White | 742 | 678.48 |
| 69 | Black | Black | 1305 | 1,193.29 |
| 70 | Cream | White | 1254 | 1,146.66 |
| 71 | Cream | White | 703 | 642.82 |
| 72 | Coriander | White | 774 | 707.75 |
| 73 | Mist | White | 701 | 640.99 |
| 74 | Verde | Green | 589 | 538.58 |
| 75 | Black | Black | 697 | 637.34 |
| 76 | Blush | Red | 1113 | 1,017.73 |
| 77 | Opal | Blue | 732 | 669.34 |
| 78 | Daffodil | Yellow | 1393 | 1,273.76 |
| 79 | Mist | White | 1496 | 1,367.94 |
| 80 | Alfalfa | Green | 1440 | 1,316.74 |
| 81 | Jade | Green | 987 | 902.51 |
| 82 | Verde | Green | 1197 | 1,094.54 |
| 83 | Cream | White | 585 | 534.92 |
| 84 | Black | Black | 1488 | 1,360.63 |
| 85 | Chocolate | Brown | 914 | 835.76 |
| 86 | Regal | Purple | 852 | 779.07 |
| 87 | Sky | White | 922 | 843.08 |
| 88 | Regal | Purple | 1339 | 1,224.38 |
| 89 | Yellow Rose | Yellow | 1311 | 1,198.78 |
| 90 | Lynx | Brown | 739 | 675.74 |
| 91 | Regal | Purple | 731 | 668.43 |
| 92 | Ash | Blue | 1485 | 1,357.88 |
| 93 | Periwinkle | Purple | 827 | 756.21 |
| 94 | Black | Black | 992 | 907.08 |
| 95 | Black | Black | 581 | 531.27 |
| 96 | Blush | Red | 708 | 647.40 |
| 97 | Regal | Purple | 1152 | 1,053.39 |
| 98 | Whirlpool | Blue | 1434 | 1,311.25 |
| 99 | Yellow Rose | Yellow | 1133 | 1,036.02 |
| 100 | Sapphire | Blue | 734 | 671.17 |
| 101 | Chocolate | Brown | 1221 | 1,116.48 |
| 102 | Toffee | Brown | 906 | 828.45 |
| 103 | Sapphire | Blue | 1423 | 1,301.19 |
| 104 | Whirlpool | Blue | 1287 | 1,176.83 |
| 105 | Black | Black | 1277 | 1,167.69 |
| 106 | Regal | Purple | 541 | 494.69 |
| 107 | Opal | Blue | 501 | 458.11 |
| 108 | Blush | Red | 1104 | 1,009.50 |
| 109 | Coriander | White | 1187 | 1,085.39 |
| 110 | Whirlpool | Blue | 1408 | 1,287.48 |
| 111 | Ash | Blue | 820 | 749.81 |
| 112 | Blush | Red | 1427 | 1,304.85 |
| 113 | Black | Black | 517 | 472.74 |
| 114 | Ruby | Red | 1279 | 1,169.52 |
| 115 | Mist | White | 788 | 720.55 |
| 116 | Chocolate | Brown | 508 | 464.52 |
| 117 | Opal | Blue | 1267 | 1,158.54 |
| 118 | Toffee | Brown | 832 | 760.78 |
| 119 | Sky | White | 981 | 897.03 |
| 120 | White | White | 1056 | 965.61 |
| 121 | Black | Black | 1145 | 1,046.99 |
| 122 | Chocolate | Brown | 1254 | 1,146.66 |
ANOVA
| Saeko owns a yarn shop and want to expands her color selection. | ||||
| Before she expands her colors, she wants to find out if her customers prefer one brand | ||||
| over another brand. Specifically, she is interested in three different types of bison yarn. | ||||
| As an experiment, she randomly selected 21 different days and recorded the sales of each brand. | ||||
| At the .10 significance level, can she conclude that there is a difference in preference between the brands? | ||||
| Misa's Bison | Yak-et-ty-Yaks | Buffalo Yarns | ||
| 799 | 776 | 799 | ||
| 784 | 640 | 931 | ||
| 807 | 822 | 794 | ||
| 675 | 856 | 920 | ||
| 795 | 616 | 731 | ||
| 875 | 893 | 837 | ||
| Total | 4,735.00 | 4,603.00 | 5,012.00 | |
| 5) | What is the null hypothesis? | |||
| What is the alternative hypothesis? | ||||
| What is the level of significance? | ||||
| 6) | Use Tools - Data Analysis - ANOVA:Single Factor | |||
| to find the F statistic: | ||||
| 7) | From the ANOVA ooutput: What is the F value? | |||
| 8) | What is the F critical value? | |||
| 9) | What is your decision? | |||
Regression
| Studies have shown that the frequency with which shoppers browse Internet retailers is related to the frequency with which they actually purchase products and/or services online. The following data show respondents age and answer to the question “How many minutes do you browse online retailers per year?” | ||
| Age (X) | Time (Y) | |
| 34 | 123,556.00 | |
| 17 | 92,425.00 | |
| 42 | 250,908.00 | |
| 35 | 204,540.00 | |
| 19 | 77,897.00 | |
| 43 | 197,012.00 | |
| 51 | 195,126.00 | |
| 50 | 177,100.00 | |
| 22 | 83,230.00 | |
| 58 | 140,012.00 | |
| 48 | 265,296.00 | |
| 35 | 189,420.00 | |
| 39 | 235,872.00 | |
| 39 | 230,724.00 | |
| 59 | 238,655.00 | |
| 40 | 138,560.00 | |
| 60 | 259,680.00 | |
| 22 | 93,208.00 | |
| 33 | 91,212.00 | |
| 36 | 153,216.00 | |
| 28 | 77,308.00 | |
| 22 | 56,496.00 | |
| 28 | 106,652.00 | |
| 44 | 242,748.00 | |
| 54 | 195,858.00 | |
| 30 | 178,560.00 | |
| 28 | 190,876.00 | |
| 16 | 98,528.00 | |
| 52 | 169,572.00 | |
| 22 | 79,420.00 | |
| 28 | 167,928.00 | |
| 35 | 215,705.00 | |
| 50 | 146,350.00 | |
| 10) | Use Data > Data Analysis > Correlation to compute the correlation checking the Labels checkbox. | |
| 11) | Use the Excel function =CORREL to compute the correlation. If answers for #1 and 2 do not agree, there is an error. | |
| The strength of the correlation motivates further examination. | ||
| 12) | a) Insert Scatter (X, Y) plot linked to the data on this sheet with Age on the horizontal (X) axis. | |
| b) Add to your chart: the chart name, vertical axis label, and horizontal axis label. | ||
| c) Complete the chart by adding Trendline and checking boxes | ||
| Read directly from the chart: | ||
| 13) | a) Intercept = | |
| b) Slope = | ||
| c) R2 = | ||
| Perform Data > Data Analysis > Regression. | ||
| 14) | Highlight the Y-intercept with yellow. Highlight the X variable in blue. Highlight the R Square in orange | |
| 15) | Use Excel to predict the number of minutes spent by a 22-year old shopper. Enter = followed by the regression formula. | |
| Enter the intercept and slope into the formula by clicking on the cells in the regression output with the results. | ||
| 16) | Is it appropriate to use this data to predict the amount of time that a 9-year-old will be on the Internet? | |
| If yes, what is the amount of time, if no, why? | ||
Cleaning Data with Outlier
| 17) | On this worksheet, make an XY scatter plot linked to the following data: | |
| X | Y | |
| 1.01 | 2.8482 | |
| 1.48 | 4.2772 | |
| 1.8 | 4.788 | |
| 1.81 | 5.3757 | |
| 1.07 | 2.5252 | |
| 1.53 | 3.0906 | |
| 1.46 | 4.3362 | |
| 1.38 | 3.2016 | |
| 1.77 | 4.3542 | |
| 1.88 | 4.8692 | |
| 1.32 | 3.8676 | |
| 1.75 | 3.9375 | |
| 1.94 | 5.7424 | |
| 1.19 | 2.4752 | |
| 1.31 | 26.2 | |
| 1.56 | 4.5708 | |
| 1.16 | 2.842 | |
| 1.22 | 2.44 | |
| 1.72 | 5.1256 | |
| 1.45 | 4.3355 | |
| 1.43 | 4.2471 | |
| 1.19 | 3.5343 | |
| 2 | 5.46 | |
| 1.6 | 3.84 | |
| 1.58 | 3.8552 | |
| 18) | Add trendline, regression equation and r squared to the plot. | |
| Add this title. ("Scatterplot of X and Y Data") | ||
| 19) | The scatterplot reveals a point outside the point pattern. Copy the data to a new location in the worksheet. You now have 2 sets of data. | |
| Data that are more tha 1.5 IQR below Q1 or more than 1.5 IQR above Q3 are considered outliers and must be investigated. | ||
| It was determined that the outlying point resulted from data entry error. Remove the outlier in the copy of the data. | ||
| Make a new scatterplot linked to the cleaned data without the outlier, and add title ("Scatterplot without Outlier,") trendline, and regression equation label. | ||
| X | Y | |
| 1.01 | 2.8482 | |
| 1.48 | 4.2772 | |
| 1.8 | 4.788 | |
| 1.81 | 5.3757 | |
| 1.07 | 2.5252 | |
| 1.53 | 3.0906 | |
| 1.46 | 4.3362 | |
| 1.38 | 3.2016 | |
| 1.77 | 4.3542 | |
| 1.88 | 4.8692 | |
| 1.32 | 3.8676 | |
| 1.75 | 3.9375 | |
| 1.94 | 5.7424 | |
| 1.19 | 2.4752 | |
| 1.56 | 4.5708 | |
| 1.16 | 2.842 | |
| 1.22 | 2.44 | |
| 1.72 | 5.1256 | |
| 1.45 | 4.3355 | |
| 1.43 | 4.2471 | |
| 1.19 | 3.5343 | |
| 2 | 5.46 | |
| 1.6 | 3.84 | |
| 1.58 | 3.8552 | |
| Compare the regression equations of the two plots. How did removal of the outlier affect the slope and R2? | ||
| 20) | ||