# Question

In this section, we mentioned that the total area under any curve representing the distribution of a variable equals 1. Explain why.

## Answer to relevant Questions

Let 0 A variable is normally distributed with mean 68 and standard deviation 10. Find the percentage of all possible values of the variable that a. Lie between 73 and 80. b. Are at least 75. c. Are at most 90. A variable is normally distributed with mean 0 and standard deviation 4. a. Determine and interpret the quartiles of the variable. b. Obtain and interpret the second decile. c. Find the value that 15% of all possible ...What is a density curve, and why are such curves important? In each of Problems 2–4, assume that the variable under consideration has a density curve. Note that the answers required here may be only approximately correct. For the standard normal curve, find the z-score(s) a. That has area 0.30 to its left b. That has area 0.10 to its right c. z0.025, z0.05, z0.01, and z0.005 d. That divide the area under the curve into a middle 0.99 area ...Post your question

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