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Advanced Alg – Unit One Data Analysis. Finding data that will give z-score. Z Score. z score =. Data – Mean σ σ : standard deviation Gives exact standard deviation of a piece of data. Find the z score. Given: Data = 93 Mean = 90 σ = 2 z score = (93 – 90) ÷ 2 = 1.5
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Advanced Alg– Unit OneData Analysis Finding data that will give z-score
Z Score z score = Data – Mean σ σ: standard deviation Gives exact standard deviation of a piece of data.
Find the z score Given: Data = 93 Mean = 90 σ = 2 z score = (93 – 90) ÷ 2 = 1.5 1.5 σ above the mean
Find the data that will give z-score Steps Use percent to find z-score Find mean and σ Plug into formula and solve for data
Given: Mean of 96 and σ = 7Find: Find data that shows less that 72% 72% = a z-score of .58 .58 = (D – 96)/ 7 7(.58) = D – 96 4.06 = D – 96 D = 4.06 + 96 D = 100.06
Given: Mean of 96 and σ = 7Find: Find data that shows less that 20% 20% = a z-score of -.85 -.85 = (D – 96)/ 7 7(-. 85) = D – 96 -5.95 = D – 96 D = -5.95 + 96 D = 90.05
Given: Mean of 96 and σ = 7Find: Find data that shows less that 98% 98% = a z-score of 2.05 2.05 = (D – 96)/ 7 7(2.05) = D – 96 14.35 = D – 96 D = 14.35 + 96 D = 110.35
Given: Mean of 96 and σ = 7Find: Find data that shows less that 72% 72% = a z-score of .68 .58 = (D – 96)/ 7 7(.58) = D – 96 4.06 = D – 96 D = 4.06 + 96 D = 100.06
Find the two pieces of data that contain 50% if Mean = 30 and σ = 5 50% of the data is between 25% and 75% (25% above and 25% below) Find z-scores for 25% and 75% z-score for 25% = -.67 z-score for 95% = .67 -.67 = (D – 30) / 5 D = 26.65 .67 = (D – 30) / 5 D = 33.35
Find the two pieces of data that contain 95% if Mean = 40 and σ = 4 95% of the data is between 2.5% and 97.5% (47.5% above and 47.5% below) Find z-scores for 2.5% and 97.5% z-score for 2.5% = -1.96 z-score for 97.5% = 1.96 -1.96 = (D – 40) / 4 D = 32.16 1.96 = (D – 40) / 4 D = 47.84