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## Statistics and probability

### Course: Statistics and probability>Unit 4

Lesson 6: Normal distribution calculations

# Basic normal calculations

Many measurements fit a special distribution called the normal distribution. In a normal distribution,
• approximately equals, 68, percent of the data falls within 1 standard deviation of the mean
• approximately equals, 95, percent of the data falls within 2 standard deviations of the mean
• approximately equals, 99, point, 7, percent of the data falls within 3 standard deviations of the mean
Problem 1
A large sample of females had their systolic blood pressure measured. The mean blood pressure was 125 millimeters of mercury and the standard deviation was 10 millimeters of mercury.
Which normal distribution below best summarizes the data?