Descriptive Statistics Mean Average of all observation Mean = (sum of all observations)/(sample size) Median The middle value of all observations If sample size is odd Median = ((n+1)/2)th largest value If the sample size is even Median = the average of the (n/2)th and ((n/2)+1)th largest value Mode The most commonly occurring value If there is more than one most commonly occurring value, there are as many modes as most commonly occurring values Types of Distributions Normal aka Gaussian, bell-shaped Mean = median = mode Bi-modal Distribution has two humps (each being a relative mode) If symmetrical, mean = median Skewed Positive Skew Asymmetrical with tail trailing off to right Mean > median > model Negative Skew Asymmetrical with tail trailing off to left Mean < median < mode Mean very sensitive to skew Median somewhat resistant to skew Mode very resistant to skew Characteristics of the Normal Distribution Defined entirely by two parameters Mean (µ) Standard deviation (σ) A certain percentage of all observations will always fall within +/- certain standard deviations of the mean +/- 1 Standard deviation = 68% +/- 2 Standard deviations = 95% +/- 3 Standard deviations = 99.7%
QUESTIONS 1 of 7 1 2 3 4 5 6 7 Previous Next (M2.OMB.18.1) A study on cholesterol levels is performed. There are 1000 participants. It is determined that in this population, the mean LDL is 200 mg/dL with a standard deviation of 50 mg/dL. If the population has a normal distribution, how many people have a cholesterol less than 300 mg/dL? QID: 210444 Type & Select Correct Answer 1 680 8% (1/12) 2 840 0% (0/12) 3 950 17% (2/12) 4 975 75% (9/12) 5 997 0% (0/12) M 5 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M2.OMB.18.1) A patient is in the ICU for diabetic ketoacidosis and is currently on an insulin drip. His electrolytes are being checked every hour and his potassium is notable for the following measures:1. 5.1 mEq/L2. 5.8 mEq/L3. 6.1 mEq/L4. 6.2 mEq/L5. 5.9 mEq/L6. 5.1 mEq/L7. 4.0 mEq/L8. 3.1 mEq/LWhich of the following is the median potassium value of this data set? QID: 210439 Type & Select Correct Answer 1 3.10 14% (2/14) 2 5.10 21% (3/14) 3 5.16 21% (3/14) 4 5.45 36% (5/14) 5 6.05 0% (0/14) M 5 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
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