Questions: Risk taking is an important part of investing. In order to make suitable investment decisions on behalf of their customers, portfolio managers give a questionnaire to new customers to measure their desire to take financial risks. The scores on the questionnaire are approximately normally distributed with a mean of 50.5 and a standard deviation of 14. The customers with scores in the bottom 15% are described as "risk averse." What is the questionnaire score that separates customers who are considered risk averse from those who are not? Carry your intermediate computations to at least four decimal places. Round your answer to one decimal place.
Transcript text: Risk taking is an important part of investing. In order to make suitable investment decisions on behalf of their customers, portfolio managers give a questionnaire to new customers to measure their desire to take financial risks. The scores on the questionnaire are approximately normally distributed with a mean of 50.5 and a standard deviation of 14. The customers with scores in the bottom 15% are described as "risk averse." What is the questionnaire score that separates customers who are considered risk averse from those who are not? Carry your intermediate computations to at least four decimal places. Round your answer to one decimal place.
Solution
Solution Steps
Step 1: Calculate the Z-Score for the 15th Percentile
To find the z-score corresponding to the 15th percentile, we use the formula for the z-score:
\[
z = \frac{X - \mu}{\sigma}
\]
For the 15th percentile, we have:
\[
z = \frac{0.15 - 0}{1} = 0.15
\]
Thus, the z-score for the 15th percentile is:
\[
z = 0.15
\]
Step 2: Convert the Z-Score to the Questionnaire Score
Next, we convert the z-score to the actual questionnaire score using the mean (\(\mu = 50.5\)) and standard deviation (\(\sigma = 14\)):
\[
X = \mu + z \cdot \sigma
\]
Substituting the values:
\[
X = 50.5 + 0.15 \cdot 14
\]
Calculating this gives:
\[
X = 50.5 + 2.1 = 52.6
\]
Final Answer
The questionnaire score that separates customers who are considered risk averse from those who are not is: