Question

the graph illustrates the \distribution of the prices of college textbooks\.
139 165 191 217 243 269 295
distribution of the prices of college textbooks
what is the mean of this normal distribution?
μ =
what is the standard deviation of this normal distribution?
σ =

Explanation:

Step1: Recall property of normal distribution mean

In a normal - distribution graph, the mean is at the center of the distribution. The data points are symmetrically distributed around the mean. The center value of the given normal - distribution of textbook prices is 217. So, $\mu = 217$.

Step2: Recall property of normal distribution standard deviation

The standard deviation $\sigma$ in a normal distribution can be found by looking at the distance between the mean and the first inflection point of the curve. The values are evenly spaced. The distance between consecutive values is 26. The first inflection point is one standard - deviation away from the mean. So, $\sigma=26$.

Answer:

$\mu = 217$
$\sigma = 26$