Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
6. Normal Distribution and Continuous Random Variables
Standard Normal Distribution
Problem 6.R.5b
Textbook Question
Birth Weights Based on Data Set 6 “Births” in Appendix B, birth weights of girls are normally distributed with a mean of 3037.1 g and a standard deviation of 706.3 g.
b. What is the value of the median?

1
Recognize that the problem involves a normal distribution, which is symmetric about its mean.
Understand that for a normal distribution, the mean, median, and mode are all equal because of the symmetry of the distribution.
Identify the given mean of the distribution, which is 3037.1 g.
Conclude that since the mean and median are the same for a normal distribution, the median is also 3037.1 g.
State that no further calculations are needed because the median is directly equal to the mean in this case.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Normal Distribution
Normal distribution is a probability distribution that is symmetric about the mean, indicating that data near the mean are more frequent in occurrence than data far from the mean. In a normal distribution, the mean, median, and mode are all equal, which simplifies the analysis of data sets that follow this pattern.
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Mean and Median
The mean is the average of a data set, calculated by summing all values and dividing by the number of values. The median, on the other hand, is the middle value when the data set is ordered. In a normal distribution, the mean and median are the same, making it straightforward to determine the median when the mean is known.
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Standard Deviation
Standard deviation is a measure of the amount of variation or dispersion in a set of values. A low standard deviation indicates that the values tend to be close to the mean, while a high standard deviation indicates that the values are spread out over a wider range. In the context of normal distribution, it helps to understand the spread of birth weights around the mean.
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