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Question ID Normal Curve From the normal curve, we know that there are 68% of the data are within one standard deviation(which is between -1o and +1a 95% are within two standard deviation (between -Zo and x + 2σ) and 99.5% are within three standard deviation(between f-3ơ and f+3c). From the figure on the left, we also notice that there are 34% of the data are between and f+10. And there are .15% of the data are above x+3o, and .15% of the data are below x-3o. 235% 19% 139 34% 34% 5% See the example in next slide and solve the following questions Question D The IQ score is a normal distribution. It has a mean of 100 and standard deviation of15 Normal Curve 1. Find the percent of the score is between 70 and 130. Solution From the normal one, we know that there are 95% of the data are between i-20 and i + 2o, which means there are 95% of the scores art between 70and 130 2. Find the percent of the score is below 73 Solution From the graph on the left, the percent of the score is below 20 means all the percent that are on the left of 20, which are .15% and 2.35% Therefore, the perent of the score is below 235% 235% 135% 235% 25% Scores: 55 70 85 10 115 130 45 3. Find the percent of the score is above 115 From the graph on the left, the percent of the score is above 115 means all the percent that are on the right of 115, which are 135%, 235% and 15% Therefore, the percent of the scores above 115 * 13.5% + 2.355+ , 15%-16%. Question D A math test is normally distributed (which means it follows the normal curve). The mean score is 88 and standard deviation is 4. 1. Find the percent of the score is between 80 and 96. 2. Find the percent of the score is between 84 and 100. 3. Find the percent of the score is below 80 4. Find the percent of the score is above 96.

Answer 1

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