Question

according to national testing data, college math class testing times are normally distributed with a mean of 45 minutes and standard deviation 3 minutes. the bell curve below represents the probability distribution for testing times. the scale on the horizontal axis is equal to the standard deviation. fill in the three indicated boxes. $mu = 45$ $sigma = 3$

Explanation:

Step1: Recall normal - distribution properties

In a normal distribution with mean $\mu$ and standard deviation $\sigma$, the values on the horizontal axis are $\mu - n\sigma,\mu-(n - 1)\sigma,\cdots,\mu+(n - 1)\sigma,\mu + n\sigma$.

Step2: Calculate the left - most value

The left - most box is likely $\mu-\sigma$. Substitute $\mu = 45$ and $\sigma = 3$ into the formula: $45-3=42$.

Step3: Calculate the middle value

The middle box is the mean $\mu$. So the value is 45.

Step4: Calculate the right - most value

The right - most box is likely $\mu+\sigma$. Substitute $\mu = 45$ and $\sigma = 3$ into the formula: $45 + 3=48$.

Answer:

42, 45, 48