The following table provides product survey results for the reliability rating of four mobile phone brands. A value of 0 represents completely unreliable and a value of 100 indicates completely reliable. Using the data in the table answer the following questions.
Reliability Scores for Mobile Phone Brands
Brand A Brand B Brand C Brand D
77 85 50 50
65 89 39 89
79 46 95 57
45 75 68 54
83 81 33 60
68 78 37 69
65 61 72 82
43 74 73 62
53 56 70 92
66 63 30 64
(a) Compute the mean, median, first quartile, and third quartile for each brand. Use the exact position, (n+1)f, where n is the number of observations and f is the relevant fraction for the quartile.
(b) Calulate the standard deviation, range and coefficient of variation from the data for each brand.
(c) Draw a box and whisker plot for the reliability of each brand and put them side by side on the same scale so that the reliability of the phones can be compared.
(d) Compare the box plots and comment on the distribution of the data.